diff --git a/1-js/5-functions-closures/6-memory-management/article.md b/1-js/5-functions-closures/6-memory-management/article.md
index 31a1c65c..91293adb 100644
--- a/1-js/5-functions-closures/6-memory-management/article.md
+++ b/1-js/5-functions-closures/6-memory-management/article.md
@@ -108,7 +108,7 @@ var family = marry({
 
 ```
 delete family.father;
-delete family.wife.husband;
+delete family.mother.husband;
 ```
 
 Обратим внимание, удаление только одной из этих ссылок ни к чему бы не привело. Пока до объекта можно добраться из корня `window`, объект остаётся жив.
diff --git a/1-js/6-objects-more/2-object-conversion/article.md b/1-js/6-objects-more/2-object-conversion/article.md
index 9e52cbdd..c45f2d2d 100644
--- a/1-js/6-objects-more/2-object-conversion/article.md
+++ b/1-js/6-objects-more/2-object-conversion/article.md
@@ -129,8 +129,9 @@ alert( +new Date() ); // valueOf: кол-во миллисекунд, проше
 
 ## Две стадии преобразования
 
-Итак, объект преобразован в примитив при помощи `toString` или `valueOf`. Далее, вполне возможно, 
-Если необходимо, что полученный из объекта примитив будет преобразован дальше, уже по правилам для примитивов.
+Итак, объект преобразован в примитив при помощи `toString` или `valueOf`. 
+
+Но на этом преобразования не обязательно заканчиваются. Вполне возможно, что в процессе вычислений этот примитив будет преобразован во что-то другое.
 
 Например, рассмотрим применение к объекту операции `==`:
 
@@ -177,22 +178,28 @@ var b = {
   }
 };
 
+alert( a + b ); // "12"
 alert( a - b ); // "1" - "2" = -1
 ```
 
 [warn header="Исключение: `Date`"]
 Объект `Date`, по историческим причинам, является исключением.
 
-Бинарный оператор плюс `+` обычно использует числовое преобразование, но в случае с `Date` -- строковое:
+Бинарный оператор плюс `+` обычно использует числовое преобразование и метод `valueOf`. Как мы уже знаем, если  подходящего `valueOf` нет (а его нет у большинства объектов), то используется `toString`, так что в итоге преобразование происходит к строке. Но если есть `valueOf`, то используется `valueOf`. Выше в примере как раз `a + b` это демонстрируют.
+
+У объектов `Date` есть и `valueOf` и `toString`. Но оператор `+` для `Date` использует именно `toString` (хотя должен бы `valueOf`).
+
+Это и есть исключение:
 
 ```js
 //+ run
-// бинарный вариант, строчное преобразование 
+// бинарный плюс, строчное преобразование 
 alert( new Date + "" ); // "строка даты"
 
-// унарный вариант, как и - * /, приводит к числу
+// унарный плюс, как и - * /, приводит к числу
 alert( +new Date ); // число миллисекунд
 ```
+Других подобных исключений нет.
 [/warn]
 
 [warn header="Как испугать Java-разработчика"]
diff --git a/1-js/6-objects-more/3-constructor-new/2-calculator-constructor/task.md b/1-js/6-objects-more/3-constructor-new/2-calculator-constructor/task.md
index bc7933a0..31258cb7 100644
--- a/1-js/6-objects-more/3-constructor-new/2-calculator-constructor/task.md
+++ b/1-js/6-objects-more/3-constructor-new/2-calculator-constructor/task.md
@@ -2,7 +2,7 @@
 
 [importance 5]
 
-Напишите *функцию-конструктор* `Calculator`, которая создает объект с двумя методами:
+Напишите *функцию-конструктор* `Calculator`, которая создает объект с тремя методами:
 <ul>
 <li>Метод `read()` запрашивает два значения при помощи `prompt` и запоминает их в свойствах объекта.</li>
 <li>Метод `sum()` возвращает сумму запомненных свойств.</li>
diff --git a/1-js/6-objects-more/4-descriptors-getters-setters/article.md b/1-js/6-objects-more/4-descriptors-getters-setters/article.md
index f1453e79..eeac2dea 100644
--- a/1-js/6-objects-more/4-descriptors-getters-setters/article.md
+++ b/1-js/6-objects-more/4-descriptors-getters-setters/article.md
@@ -283,6 +283,8 @@ alert( pete.birthday ); // и дата рождения доступна
 alert( pete.age );      // и возраст
 ```
 
+Заметим, что `pete.age` снаружи как было свойством, так и осталось. То есть, переписывать внешний код на вызов функции `pete.age()` не нужно.
+
 Таким образом, `defineProperty` позволяет нам начать с обычных свойств, а в будущем, при необходимости, можно в любой момент заменить их на функции, реализующие более сложную логику.
 
 ## Другие методы работы со свойствами
diff --git a/12-extra/10-cookie/article.md b/10-extra/10-cookie/article.md
similarity index 100%
rename from 12-extra/10-cookie/article.md
rename to 10-extra/10-cookie/article.md
diff --git a/12-extra/10-cookie/cookie.js b/10-extra/10-cookie/cookie.js
similarity index 100%
rename from 12-extra/10-cookie/cookie.js
rename to 10-extra/10-cookie/cookie.js
diff --git a/12-extra/10-cookie/safari-nocookie.png b/10-extra/10-cookie/safari-nocookie.png
similarity index 100%
rename from 12-extra/10-cookie/safari-nocookie.png
rename to 10-extra/10-cookie/safari-nocookie.png
diff --git a/12-extra/10-cookie/safari-nocookie@2x.png b/10-extra/10-cookie/safari-nocookie@2x.png
similarity index 100%
rename from 12-extra/10-cookie/safari-nocookie@2x.png
rename to 10-extra/10-cookie/safari-nocookie@2x.png
diff --git a/12-extra/11-intl/1-collate-array-sort/solution.md b/10-extra/11-intl/1-collate-array-sort/solution.md
similarity index 100%
rename from 12-extra/11-intl/1-collate-array-sort/solution.md
rename to 10-extra/11-intl/1-collate-array-sort/solution.md
diff --git a/12-extra/11-intl/1-collate-array-sort/task.md b/10-extra/11-intl/1-collate-array-sort/task.md
similarity index 100%
rename from 12-extra/11-intl/1-collate-array-sort/task.md
rename to 10-extra/11-intl/1-collate-array-sort/task.md
diff --git a/12-extra/11-intl/article.md b/10-extra/11-intl/article.md
similarity index 100%
rename from 12-extra/11-intl/article.md
rename to 10-extra/11-intl/article.md
diff --git a/12-extra/12-regexp-specials/article.md b/10-extra/12-regexp-specials/article.md
similarity index 100%
rename from 12-extra/12-regexp-specials/article.md
rename to 10-extra/12-regexp-specials/article.md
diff --git a/12-extra/3-templates/article.md b/10-extra/3-templates/article.md
similarity index 100%
rename from 12-extra/3-templates/article.md
rename to 10-extra/3-templates/article.md
diff --git a/12-extra/4-books/article.md b/10-extra/4-books/article.md
similarity index 100%
rename from 12-extra/4-books/article.md
rename to 10-extra/4-books/article.md
diff --git a/12-extra/5-setImmediate/article.md b/10-extra/5-setImmediate/article.md
similarity index 100%
rename from 12-extra/5-setImmediate/article.md
rename to 10-extra/5-setImmediate/article.md
diff --git a/12-extra/5-setImmediate/setImmediate.view/index.html b/10-extra/5-setImmediate/setImmediate.view/index.html
similarity index 100%
rename from 12-extra/5-setImmediate/setImmediate.view/index.html
rename to 10-extra/5-setImmediate/setImmediate.view/index.html
diff --git a/12-extra/5-setImmediate/setImmediate.view/setImmediate.js b/10-extra/5-setImmediate/setImmediate.view/setImmediate.js
similarity index 100%
rename from 12-extra/5-setImmediate/setImmediate.view/setImmediate.js
rename to 10-extra/5-setImmediate/setImmediate.view/setImmediate.js
diff --git a/12-extra/6-bind-late/article.md b/10-extra/6-bind-late/article.md
similarity index 100%
rename from 12-extra/6-bind-late/article.md
rename to 10-extra/6-bind-late/article.md
diff --git a/12-extra/7-sublime/article.md b/10-extra/7-sublime/article.md
similarity index 100%
rename from 12-extra/7-sublime/article.md
rename to 10-extra/7-sublime/article.md
diff --git a/12-extra/7-sublime/sheet.pdf b/10-extra/7-sublime/sheet.pdf
similarity index 100%
rename from 12-extra/7-sublime/sheet.pdf
rename to 10-extra/7-sublime/sheet.pdf
diff --git a/12-extra/8-range-textrange-selection/56.gif b/10-extra/8-range-textrange-selection/56.gif
similarity index 100%
rename from 12-extra/8-range-textrange-selection/56.gif
rename to 10-extra/8-range-textrange-selection/56.gif
diff --git a/12-extra/8-range-textrange-selection/57.gif b/10-extra/8-range-textrange-selection/57.gif
similarity index 100%
rename from 12-extra/8-range-textrange-selection/57.gif
rename to 10-extra/8-range-textrange-selection/57.gif
diff --git a/12-extra/8-range-textrange-selection/58.gif b/10-extra/8-range-textrange-selection/58.gif
similarity index 100%
rename from 12-extra/8-range-textrange-selection/58.gif
rename to 10-extra/8-range-textrange-selection/58.gif
diff --git a/12-extra/8-range-textrange-selection/article.md b/10-extra/8-range-textrange-selection/article.md
similarity index 100%
rename from 12-extra/8-range-textrange-selection/article.md
rename to 10-extra/8-range-textrange-selection/article.md
diff --git a/12-extra/8-range-textrange-selection/domRangeCreate.view/index.html b/10-extra/8-range-textrange-selection/domRangeCreate.view/index.html
similarity index 100%
rename from 12-extra/8-range-textrange-selection/domRangeCreate.view/index.html
rename to 10-extra/8-range-textrange-selection/domRangeCreate.view/index.html
diff --git a/12-extra/8-range-textrange-selection/domRangeHighlight.view/index.html b/10-extra/8-range-textrange-selection/domRangeHighlight.view/index.html
similarity index 100%
rename from 12-extra/8-range-textrange-selection/domRangeHighlight.view/index.html
rename to 10-extra/8-range-textrange-selection/domRangeHighlight.view/index.html
diff --git a/12-extra/8-range-textrange-selection/fix-ie.view/fixIERangeObject.js b/10-extra/8-range-textrange-selection/fix-ie.view/fixIERangeObject.js
similarity index 100%
rename from 12-extra/8-range-textrange-selection/fix-ie.view/fixIERangeObject.js
rename to 10-extra/8-range-textrange-selection/fix-ie.view/fixIERangeObject.js
diff --git a/12-extra/8-range-textrange-selection/fix-ie.view/index.html b/10-extra/8-range-textrange-selection/fix-ie.view/index.html
similarity index 100%
rename from 12-extra/8-range-textrange-selection/fix-ie.view/index.html
rename to 10-extra/8-range-textrange-selection/fix-ie.view/index.html
diff --git a/12-extra/8-range-textrange-selection/ieTextRangeHighlight.view/index.html b/10-extra/8-range-textrange-selection/ieTextRangeHighlight.view/index.html
similarity index 100%
rename from 12-extra/8-range-textrange-selection/ieTextRangeHighlight.view/index.html
rename to 10-extra/8-range-textrange-selection/ieTextRangeHighlight.view/index.html
diff --git a/12-extra/8-range-textrange-selection/setSelection.view/index.html b/10-extra/8-range-textrange-selection/setSelection.view/index.html
similarity index 100%
rename from 12-extra/8-range-textrange-selection/setSelection.view/index.html
rename to 10-extra/8-range-textrange-selection/setSelection.view/index.html
diff --git a/12-extra/9-drag-and-drop-plus/DragAvatar.js b/10-extra/9-drag-and-drop-plus/DragAvatar.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/DragAvatar.js
rename to 10-extra/9-drag-and-drop-plus/DragAvatar.js
diff --git a/12-extra/9-drag-and-drop-plus/DragManager.js b/10-extra/9-drag-and-drop-plus/DragManager.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/DragManager.js
rename to 10-extra/9-drag-and-drop-plus/DragManager.js
diff --git a/12-extra/9-drag-and-drop-plus/DragZone.js b/10-extra/9-drag-and-drop-plus/DragZone.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/DragZone.js
rename to 10-extra/9-drag-and-drop-plus/DragZone.js
diff --git a/12-extra/9-drag-and-drop-plus/DropTarget.js b/10-extra/9-drag-and-drop-plus/DropTarget.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/DropTarget.js
rename to 10-extra/9-drag-and-drop-plus/DropTarget.js
diff --git a/12-extra/9-drag-and-drop-plus/TreeDragAvatar.js b/10-extra/9-drag-and-drop-plus/TreeDragAvatar.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/TreeDragAvatar.js
rename to 10-extra/9-drag-and-drop-plus/TreeDragAvatar.js
diff --git a/12-extra/9-drag-and-drop-plus/TreeDragZone.js b/10-extra/9-drag-and-drop-plus/TreeDragZone.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/TreeDragZone.js
rename to 10-extra/9-drag-and-drop-plus/TreeDragZone.js
diff --git a/12-extra/9-drag-and-drop-plus/TreeDropTarget.js b/10-extra/9-drag-and-drop-plus/TreeDropTarget.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/TreeDropTarget.js
rename to 10-extra/9-drag-and-drop-plus/TreeDropTarget.js
diff --git a/12-extra/9-drag-and-drop-plus/article.md b/10-extra/9-drag-and-drop-plus/article.md
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/article.md
rename to 10-extra/9-drag-and-drop-plus/article.md
diff --git a/12-extra/9-drag-and-drop-plus/dragTree.view/DragAvatar.js b/10-extra/9-drag-and-drop-plus/dragTree.view/DragAvatar.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragTree.view/DragAvatar.js
rename to 10-extra/9-drag-and-drop-plus/dragTree.view/DragAvatar.js
diff --git a/12-extra/9-drag-and-drop-plus/dragTree.view/DragManager.js b/10-extra/9-drag-and-drop-plus/dragTree.view/DragManager.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragTree.view/DragManager.js
rename to 10-extra/9-drag-and-drop-plus/dragTree.view/DragManager.js
diff --git a/12-extra/9-drag-and-drop-plus/dragTree.view/DragZone.js b/10-extra/9-drag-and-drop-plus/dragTree.view/DragZone.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragTree.view/DragZone.js
rename to 10-extra/9-drag-and-drop-plus/dragTree.view/DragZone.js
diff --git a/12-extra/9-drag-and-drop-plus/dragTree.view/DropTarget.js b/10-extra/9-drag-and-drop-plus/dragTree.view/DropTarget.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragTree.view/DropTarget.js
rename to 10-extra/9-drag-and-drop-plus/dragTree.view/DropTarget.js
diff --git a/12-extra/9-drag-and-drop-plus/dragTree.view/TreeDragAvatar.js b/10-extra/9-drag-and-drop-plus/dragTree.view/TreeDragAvatar.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragTree.view/TreeDragAvatar.js
rename to 10-extra/9-drag-and-drop-plus/dragTree.view/TreeDragAvatar.js
diff --git a/12-extra/9-drag-and-drop-plus/dragTree.view/TreeDragZone.js b/10-extra/9-drag-and-drop-plus/dragTree.view/TreeDragZone.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragTree.view/TreeDragZone.js
rename to 10-extra/9-drag-and-drop-plus/dragTree.view/TreeDragZone.js
diff --git a/12-extra/9-drag-and-drop-plus/dragTree.view/TreeDropTarget.js b/10-extra/9-drag-and-drop-plus/dragTree.view/TreeDropTarget.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragTree.view/TreeDropTarget.js
rename to 10-extra/9-drag-and-drop-plus/dragTree.view/TreeDropTarget.js
diff --git a/12-extra/9-drag-and-drop-plus/dragTree.view/dragTree.css b/10-extra/9-drag-and-drop-plus/dragTree.view/dragTree.css
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragTree.view/dragTree.css
rename to 10-extra/9-drag-and-drop-plus/dragTree.view/dragTree.css
diff --git a/12-extra/9-drag-and-drop-plus/dragTree.view/index.html b/10-extra/9-drag-and-drop-plus/dragTree.view/index.html
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragTree.view/index.html
rename to 10-extra/9-drag-and-drop-plus/dragTree.view/index.html
diff --git a/12-extra/9-drag-and-drop-plus/dragTree.view/lib.js b/10-extra/9-drag-and-drop-plus/dragTree.view/lib.js
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragTree.view/lib.js
rename to 10-extra/9-drag-and-drop-plus/dragTree.view/lib.js
diff --git a/12-extra/9-drag-and-drop-plus/dragzonetarget.png b/10-extra/9-drag-and-drop-plus/dragzonetarget.png
similarity index 100%
rename from 12-extra/9-drag-and-drop-plus/dragzonetarget.png
rename to 10-extra/9-drag-and-drop-plus/dragzonetarget.png
diff --git a/12-extra/index.md b/10-extra/index.md
similarity index 100%
rename from 12-extra/index.md
rename to 10-extra/index.md
diff --git a/10-regular-expressions-javascript/1-regexp-introduction/article.md b/11-regular-expressions-javascript/1-regexp-introduction/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/1-regexp-introduction/article.md
rename to 11-regular-expressions-javascript/1-regexp-introduction/article.md
diff --git a/11-regular-expressions-javascript/10-regexp-backreferences/1-find-matching-bbtags/solution.md b/11-regular-expressions-javascript/10-regexp-backreferences/1-find-matching-bbtags/solution.md
new file mode 100644
index 00000000..234032d4
--- /dev/null
+++ b/11-regular-expressions-javascript/10-regexp-backreferences/1-find-matching-bbtags/solution.md
@@ -0,0 +1,21 @@
+
+Открывающий тег -- это <code class="pattern">\[(b|url|quote)\]</code>.
+
+Для того, чтобы найти всё до закрывающего -- используем ленивый поиск <code class="pattern">[\s\S]*?</code> и обратную ссылку на открывающий тег.
+
+Итого, получится: <code class="pattern">\[(b|url|quote)\][\s\S]*?\[/\1\]</code>.
+
+В действии:
+
+```js
+//+ run
+var re = /\[(b|url|quote)\][\s\S]*?\[\/\1\]/g;
+
+var str1 = "..[url]http://ya.ru[/url]..";
+var str2 = "..[url][b]http://ya.ru[/b][/url]..";
+
+alert( str1.match(re) ); // [url]http://ya.ru[/url]
+alert( str2.match(re) ); // [url][b]http://ya.ru[/b][/url]
+```
+
+Для закрывающего тега `[/1]` понадобилось дополнительно экранировать слеш: `\[\/1\]`.
diff --git a/11-regular-expressions-javascript/10-regexp-backreferences/1-find-matching-bbtags/task.md b/11-regular-expressions-javascript/10-regexp-backreferences/1-find-matching-bbtags/task.md
new file mode 100644
index 00000000..8596bed5
--- /dev/null
+++ b/11-regular-expressions-javascript/10-regexp-backreferences/1-find-matching-bbtags/task.md
@@ -0,0 +1,41 @@
+# Найдите пары тегов
+
+ББ-тег имеет вид `[имя]...[/имя]`, где имя -- слово, одно из: `b`, `url`, `quote`.
+
+Например:
+```
+[b]текст[/b]
+[url]http://ya.ru[/url]
+```
+
+ББ-теги могут быть вложенными, но сам в себя тег быть вложен не может, например:
+
+```
+Допустимо:
+[url] [b]http://ya.ru[/b] [/url]
+[quote] [b]текст[/b] [/quote]
+
+Нельзя:
+[b][b]текст[/b][/b]
+```
+
+Создайте регулярное выражение для поиска ББ-тегов и их содержимого.
+
+Например:
+
+```js
+var re = /* регулярка */
+
+var str = "..[url]http://ya.ru[/url]..";
+alert( str.match(re) ); // [url]http://ya.ru[/url]
+```
+
+Если теги вложены, то нужно искать самый внешний тег (при желании можно будет продолжить поиск в его содержимом):
+
+```js
+var re = /* регулярка */
+
+var str = "..[url][b]http://ya.ru[/b][/url]..";
+alert( str.match(re) ); // [url][b]http://ya.ru[/b][/url]
+```
+
diff --git a/10-regular-expressions-javascript/10-regexp-backreferences/article.md b/11-regular-expressions-javascript/10-regexp-backreferences/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/10-regexp-backreferences/article.md
rename to 11-regular-expressions-javascript/10-regexp-backreferences/article.md
diff --git a/10-regular-expressions-javascript/12-regexp-alternation/article.md b/11-regular-expressions-javascript/12-regexp-alternation/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/12-regexp-alternation/article.md
rename to 11-regular-expressions-javascript/12-regexp-alternation/article.md
diff --git a/10-regular-expressions-javascript/13-regexp-ahchors-and-multiline-mode/article.md b/11-regular-expressions-javascript/13-regexp-ahchors-and-multiline-mode/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/13-regexp-ahchors-and-multiline-mode/article.md
rename to 11-regular-expressions-javascript/13-regexp-ahchors-and-multiline-mode/article.md
diff --git a/10-regular-expressions-javascript/14-regexp-multiline-mode/article.md b/11-regular-expressions-javascript/14-regexp-multiline-mode/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/14-regexp-multiline-mode/article.md
rename to 11-regular-expressions-javascript/14-regexp-multiline-mode/article.md
diff --git a/10-regular-expressions-javascript/15-regexp-word-boundary/article.md b/11-regular-expressions-javascript/15-regexp-word-boundary/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/15-regexp-word-boundary/article.md
rename to 11-regular-expressions-javascript/15-regexp-word-boundary/article.md
diff --git a/10-regular-expressions-javascript/15-regexp-word-boundary/boundary1.png b/11-regular-expressions-javascript/15-regexp-word-boundary/boundary1.png
similarity index 100%
rename from 10-regular-expressions-javascript/15-regexp-word-boundary/boundary1.png
rename to 11-regular-expressions-javascript/15-regexp-word-boundary/boundary1.png
diff --git a/10-regular-expressions-javascript/15-regexp-word-boundary/boundary2.png b/11-regular-expressions-javascript/15-regexp-word-boundary/boundary2.png
similarity index 100%
rename from 10-regular-expressions-javascript/15-regexp-word-boundary/boundary2.png
rename to 11-regular-expressions-javascript/15-regexp-word-boundary/boundary2.png
diff --git a/10-regular-expressions-javascript/15-regexp-word-boundary/boundary3.png b/11-regular-expressions-javascript/15-regexp-word-boundary/boundary3.png
similarity index 100%
rename from 10-regular-expressions-javascript/15-regexp-word-boundary/boundary3.png
rename to 11-regular-expressions-javascript/15-regexp-word-boundary/boundary3.png
diff --git a/10-regular-expressions-javascript/15-regexp-word-boundary/boundary4.png b/11-regular-expressions-javascript/15-regexp-word-boundary/boundary4.png
similarity index 100%
rename from 10-regular-expressions-javascript/15-regexp-word-boundary/boundary4.png
rename to 11-regular-expressions-javascript/15-regexp-word-boundary/boundary4.png
diff --git a/10-regular-expressions-javascript/16-regexp-todo/article.md b/11-regular-expressions-javascript/16-regexp-todo/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/16-regexp-todo/article.md
rename to 11-regular-expressions-javascript/16-regexp-todo/article.md
diff --git a/10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/article.md b/11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/article.md
rename to 11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/article.md
diff --git a/10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy1.png b/11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy1.png
similarity index 100%
rename from 10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy1.png
rename to 11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy1.png
diff --git a/10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy11.png b/11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy11.png
similarity index 100%
rename from 10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy11.png
rename to 11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy11.png
diff --git a/10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy2.png b/11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy2.png
similarity index 100%
rename from 10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy2.png
rename to 11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy2.png
diff --git a/10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy3.png b/11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy3.png
similarity index 100%
rename from 10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy3.png
rename to 11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy3.png
diff --git a/10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy4.png b/11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy4.png
similarity index 100%
rename from 10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy4.png
rename to 11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy4.png
diff --git a/10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy5.png b/11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy5.png
similarity index 100%
rename from 10-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy5.png
rename to 11-regular-expressions-javascript/17-regexp-infinite-backtracking-problem/bad_backtrack_greedy5.png
diff --git a/10-regular-expressions-javascript/18-regexp-orphans/article.md b/11-regular-expressions-javascript/18-regexp-orphans/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/18-regexp-orphans/article.md
rename to 11-regular-expressions-javascript/18-regexp-orphans/article.md
diff --git a/10-regular-expressions-javascript/2-regexp-methods/article.md b/11-regular-expressions-javascript/2-regexp-methods/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/2-regexp-methods/article.md
rename to 11-regular-expressions-javascript/2-regexp-methods/article.md
diff --git a/10-regular-expressions-javascript/3-regexp-character-classes/1-find-time-hh-mm/solution.md b/11-regular-expressions-javascript/3-regexp-character-classes/1-find-time-hh-mm/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/3-regexp-character-classes/1-find-time-hh-mm/solution.md
rename to 11-regular-expressions-javascript/3-regexp-character-classes/1-find-time-hh-mm/solution.md
diff --git a/10-regular-expressions-javascript/3-regexp-character-classes/1-find-time-hh-mm/task.md b/11-regular-expressions-javascript/3-regexp-character-classes/1-find-time-hh-mm/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/3-regexp-character-classes/1-find-time-hh-mm/task.md
rename to 11-regular-expressions-javascript/3-regexp-character-classes/1-find-time-hh-mm/task.md
diff --git a/10-regular-expressions-javascript/3-regexp-character-classes/article.md b/11-regular-expressions-javascript/3-regexp-character-classes/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/3-regexp-character-classes/article.md
rename to 11-regular-expressions-javascript/3-regexp-character-classes/article.md
diff --git a/10-regular-expressions-javascript/3-regexp-character-classes/love_html5.png b/11-regular-expressions-javascript/3-regexp-character-classes/love_html5.png
similarity index 100%
rename from 10-regular-expressions-javascript/3-regexp-character-classes/love_html5.png
rename to 11-regular-expressions-javascript/3-regexp-character-classes/love_html5.png
diff --git a/10-regular-expressions-javascript/5-regexp-character-sets-and-ranges/1-find-range-1/solution.md b/11-regular-expressions-javascript/5-regexp-character-sets-and-ranges/1-find-range-1/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/5-regexp-character-sets-and-ranges/1-find-range-1/solution.md
rename to 11-regular-expressions-javascript/5-regexp-character-sets-and-ranges/1-find-range-1/solution.md
diff --git a/10-regular-expressions-javascript/5-regexp-character-sets-and-ranges/1-find-range-1/task.md b/11-regular-expressions-javascript/5-regexp-character-sets-and-ranges/1-find-range-1/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/5-regexp-character-sets-and-ranges/1-find-range-1/task.md
rename to 11-regular-expressions-javascript/5-regexp-character-sets-and-ranges/1-find-range-1/task.md
diff --git a/10-regular-expressions-javascript/5-regexp-character-sets-and-ranges/2-find-time-2-formats/solution.md b/11-regular-expressions-javascript/5-regexp-character-sets-and-ranges/2-find-time-2-formats/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/5-regexp-character-sets-and-ranges/2-find-time-2-formats/solution.md
rename to 11-regular-expressions-javascript/5-regexp-character-sets-and-ranges/2-find-time-2-formats/solution.md
diff --git a/10-regular-expressions-javascript/5-regexp-character-sets-and-ranges/2-find-time-2-formats/task.md b/11-regular-expressions-javascript/5-regexp-character-sets-and-ranges/2-find-time-2-formats/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/5-regexp-character-sets-and-ranges/2-find-time-2-formats/task.md
rename to 11-regular-expressions-javascript/5-regexp-character-sets-and-ranges/2-find-time-2-formats/task.md
diff --git a/10-regular-expressions-javascript/5-regexp-character-sets-and-ranges/article.md b/11-regular-expressions-javascript/5-regexp-character-sets-and-ranges/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/5-regexp-character-sets-and-ranges/article.md
rename to 11-regular-expressions-javascript/5-regexp-character-sets-and-ranges/article.md
diff --git a/10-regular-expressions-javascript/7-regexp-quantifiers/1-find-text-manydots/solution.md b/11-regular-expressions-javascript/7-regexp-quantifiers/1-find-text-manydots/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/7-regexp-quantifiers/1-find-text-manydots/solution.md
rename to 11-regular-expressions-javascript/7-regexp-quantifiers/1-find-text-manydots/solution.md
diff --git a/10-regular-expressions-javascript/7-regexp-quantifiers/1-find-text-manydots/task.md b/11-regular-expressions-javascript/7-regexp-quantifiers/1-find-text-manydots/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/7-regexp-quantifiers/1-find-text-manydots/task.md
rename to 11-regular-expressions-javascript/7-regexp-quantifiers/1-find-text-manydots/task.md
diff --git a/10-regular-expressions-javascript/7-regexp-quantifiers/2-find-html-colors-6hex/solution.md b/11-regular-expressions-javascript/7-regexp-quantifiers/2-find-html-colors-6hex/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/7-regexp-quantifiers/2-find-html-colors-6hex/solution.md
rename to 11-regular-expressions-javascript/7-regexp-quantifiers/2-find-html-colors-6hex/solution.md
diff --git a/10-regular-expressions-javascript/7-regexp-quantifiers/2-find-html-colors-6hex/task.md b/11-regular-expressions-javascript/7-regexp-quantifiers/2-find-html-colors-6hex/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/7-regexp-quantifiers/2-find-html-colors-6hex/task.md
rename to 11-regular-expressions-javascript/7-regexp-quantifiers/2-find-html-colors-6hex/task.md
diff --git a/10-regular-expressions-javascript/7-regexp-quantifiers/3-find-decimal-positive-numbers/solution.md b/11-regular-expressions-javascript/7-regexp-quantifiers/3-find-decimal-positive-numbers/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/7-regexp-quantifiers/3-find-decimal-positive-numbers/solution.md
rename to 11-regular-expressions-javascript/7-regexp-quantifiers/3-find-decimal-positive-numbers/solution.md
diff --git a/10-regular-expressions-javascript/7-regexp-quantifiers/3-find-decimal-positive-numbers/task.md b/11-regular-expressions-javascript/7-regexp-quantifiers/3-find-decimal-positive-numbers/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/7-regexp-quantifiers/3-find-decimal-positive-numbers/task.md
rename to 11-regular-expressions-javascript/7-regexp-quantifiers/3-find-decimal-positive-numbers/task.md
diff --git a/10-regular-expressions-javascript/7-regexp-quantifiers/4-find-decimal-numbers/solution.md b/11-regular-expressions-javascript/7-regexp-quantifiers/4-find-decimal-numbers/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/7-regexp-quantifiers/4-find-decimal-numbers/solution.md
rename to 11-regular-expressions-javascript/7-regexp-quantifiers/4-find-decimal-numbers/solution.md
diff --git a/10-regular-expressions-javascript/7-regexp-quantifiers/4-find-decimal-numbers/task.md b/11-regular-expressions-javascript/7-regexp-quantifiers/4-find-decimal-numbers/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/7-regexp-quantifiers/4-find-decimal-numbers/task.md
rename to 11-regular-expressions-javascript/7-regexp-quantifiers/4-find-decimal-numbers/task.md
diff --git a/10-regular-expressions-javascript/7-regexp-quantifiers/article.md b/11-regular-expressions-javascript/7-regexp-quantifiers/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/7-regexp-quantifiers/article.md
rename to 11-regular-expressions-javascript/7-regexp-quantifiers/article.md
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/1-lazy-greedy/solution.md b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/1-lazy-greedy/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/1-lazy-greedy/solution.md
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/1-lazy-greedy/solution.md
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/1-lazy-greedy/task.md b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/1-lazy-greedy/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/1-lazy-greedy/task.md
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/1-lazy-greedy/task.md
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/2-difference-find-quote/solution.md b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/2-difference-find-quote/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/2-difference-find-quote/solution.md
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/2-difference-find-quote/solution.md
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/2-difference-find-quote/task.md b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/2-difference-find-quote/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/2-difference-find-quote/task.md
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/2-difference-find-quote/task.md
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/3-find-html-comments/solution.md b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/3-find-html-comments/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/3-find-html-comments/solution.md
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/3-find-html-comments/solution.md
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/3-find-html-comments/task.md b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/3-find-html-comments/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/3-find-html-comments/task.md
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/3-find-html-comments/task.md
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/4-find-html-tags-greedy-lazy/solution.md b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/4-find-html-tags-greedy-lazy/solution.md
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/4-find-html-tags-greedy-lazy/solution.md
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/4-find-html-tags-greedy-lazy/solution.md
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/4-find-html-tags-greedy-lazy/task.md b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/4-find-html-tags-greedy-lazy/task.md
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/4-find-html-tags-greedy-lazy/task.md
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/4-find-html-tags-greedy-lazy/task.md
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/article.md b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/article.md
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/article.md
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy1.svg b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy1.svg
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy1.svg
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy1.svg
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy2.svg b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy2.svg
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy2.svg
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy2.svg
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy3.svg b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy3.svg
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy3.svg
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy3.svg
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy4.svg b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy4.svg
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy4.svg
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy4.svg
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy5.svg b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy5.svg
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy5.svg
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy5.svg
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy6.svg b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy6.svg
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy6.svg
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_greedy6.svg
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy3.svg b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy3.svg
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy3.svg
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy3.svg
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy4.svg b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy4.svg
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy4.svg
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy4.svg
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy5.svg b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy5.svg
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy5.svg
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy5.svg
diff --git a/10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy6.svg b/11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy6.svg
similarity index 100%
rename from 10-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy6.svg
rename to 11-regular-expressions-javascript/8-regexp-greedy-and-lazy/witch_lazy6.svg
diff --git a/11-regular-expressions-javascript/9-regexp-groups/1-find-webcolor-3-or-6/solution.md b/11-regular-expressions-javascript/9-regexp-groups/1-find-webcolor-3-or-6/solution.md
new file mode 100644
index 00000000..78bea60d
--- /dev/null
+++ b/11-regular-expressions-javascript/9-regexp-groups/1-find-webcolor-3-or-6/solution.md
@@ -0,0 +1,21 @@
+Регулярное выражение для поиска 3-значного цвета: <code class="pattern">/#[a-f0-9]{3}/i</code>.
+
+Нужно добавить ещё три символа, причём нужны именно три, четыре или семь символов не нужны. Эти три символа либо есть, либо нет.
+
+Самый простой способ добавить -- просто дописать в конец регэкспа: <code class="pattern">/#[a-f0-9]{3}([a-f0-9]{3})?/i</code>
+
+Можно поступить и хитрее: <code class="pattern">/#([a-f0-9]{3}){1,2}/i</code>.
+
+Здесь регэксп <code class="pattern">[a-f0-9]{3}</code> заключён в скобки, чтобы квантификатор <code class="pattern">{1,2}</code> применялся целиком ко всей этой структуре.
+
+В действии:
+```js
+//+ run
+var re = /#([a-f0-9]{3}){1,2}/gi;
+
+var str = "color: #3f3; background-color: #AA00ef; and: #abcd";
+
+alert( str.match(re) ); // #3f3 #AA0ef #abc
+```
+
+
diff --git a/11-regular-expressions-javascript/9-regexp-groups/1-find-webcolor-3-or-6/task.md b/11-regular-expressions-javascript/9-regexp-groups/1-find-webcolor-3-or-6/task.md
new file mode 100644
index 00000000..000555ac
--- /dev/null
+++ b/11-regular-expressions-javascript/9-regexp-groups/1-find-webcolor-3-or-6/task.md
@@ -0,0 +1,14 @@
+# Найдите цвет в формате #abc или #abcdef
+
+Напишите регулярное выражение, которое находит цвет в формате `#abc` или `#abcdef`. То есть, символ `#`, после которого идут 3 или 6 шестнадцатиричных символа.
+
+Пример использования:
+```js
+var re = /* ваш регэксп */
+
+var str = "color: #3f3; background-color: #AA00ef; and: #abcd";
+
+alert( str.match(re) ); // #3f3 #AA0ef
+```
+
+P.S. Значения из четырёх и более букв, такие как `#abcd` мы в этой задаче также учитываем, но берём из них только необходимые для совпадения символы, то есть `#abc`.
diff --git a/11-regular-expressions-javascript/9-regexp-groups/2-parse-expression/solution.md b/11-regular-expressions-javascript/9-regexp-groups/2-parse-expression/solution.md
new file mode 100644
index 00000000..05fedcd8
--- /dev/null
+++ b/11-regular-expressions-javascript/9-regexp-groups/2-parse-expression/solution.md
@@ -0,0 +1,53 @@
+Регулярное выражение для числа, возможно, дробного и отрицательного: <code class="pattern">-?\d+(\.\d+)?</code>. Мы уже разбирали его в предыдущих задачах.
+
+Оператор -- это <code class="pattern">[-+*/]</code>. Заметим, что дефис <code class="pattern">-</code> идёт в списке первым, так как на любой позиции, кроме первой и последней, он имеет специальный смысл внутри <code class="pattern">[...]</code>, и его понадобилось бы экранировать.
+
+Кроме того, когда мы оформим это в JavaScript-синтаксис <code class="pattern">/.../</code> -- понадобится заэкранировать слэш <code class="pattern">/</code>.
+
+Нам нужно число, затем оператор, затем число, и необязательные пробелы между ними.
+
+Полное регулярное выражение будет таким: <code class="pattern">-?\d+(\.\d+)?\s*[-+*/]\s*-?\d+(\.\d+)?</code>. 
+
+Чтобы получить результат в виде массива, добавим скобки вокруг тех данных, которые нам интересны, то есть -- вокруг чисел и оператора: <code class="pattern">(-?\d+(\.\d+)?)\s*([-+*/])\s*(-?\d+(\.\d+)?)</code>.
+
+Посмотрим в действии:
+```js
+//+ run
+var re = /(-?\d+(\.\d+)?)\s*([-+*\/])\s*(-?\d+(\.\d+)?)/;
+
+alert( "1.2 + 12".match(re) );
+```
+
+Итоговый массив будет включать в себя компоненты:
+
+<ul>
+<li>`result[0] == "1.2 + 12"` (вначале всегда полное совпадение)</li>
+<li>`result[1] == "1"` (первая скобка)</li>
+<li>`result[2] == "2"` (вторая скобка -- дробная часть `(\.\d+)?`)</li>
+<li>`result[3] == "+"` (...)</li>
+<li>`result[4] == "12"` (...)</li>
+<li>`result[5] == undefined` (последняя скобка, но у второго числа дробная часть отсутствует)</li>
+</ul>
+
+Нам из этого массива нужны только числа и оператор. А, скажем, дробная часть сама по себе -- не нужна.
+
+Уберём её из запоминания, добавив в начало скобки <code class="pattern">?:</code>, то есть: <code class="pattern">(?:\.\d+)?</code>.
+
+Итого, решение:
+
+```js
+//+ run
+function parse(expr) {
+  var re = /(-?\d+(?:\.\d+)?)\s*([-+*\/])\s*(-?\d+(?:\.\d+)?)/;
+
+  var result = expr.match(re);
+
+  if (!result) return;
+  result.shift();
+
+  return result;
+}
+
+alert( parse("-1.23 * 3.45") );  // -1.23, *, 3.45
+```
+
diff --git a/11-regular-expressions-javascript/9-regexp-groups/2-parse-expression/task.md b/11-regular-expressions-javascript/9-regexp-groups/2-parse-expression/task.md
new file mode 100644
index 00000000..353ae5f4
--- /dev/null
+++ b/11-regular-expressions-javascript/9-regexp-groups/2-parse-expression/task.md
@@ -0,0 +1,20 @@
+# Разобрать выражение
+
+Арифметическое выражение состоит из двух чисел и операции между ними, например:
+<ul>
+<li>`1 + 2`</li>
+<li>`1.2 * 3.4`</li>
+<li>`-3 / -6`</li>
+<li>-2 - 2`</li>
+</ul>
+
+Список операций: `"+"`, `"-"`, `"*"` и `"/"`.
+
+Также могут присутсововать пробелы вокруг оператора и чисел.
+
+Напишите функцию, которая будет получать выражение и возвращать массив из трёх аргументов:
+<ol>
+<li>Первое число.</li>
+<li>Оператор.</li>
+<li>Второе число.</li>
+</ul>
diff --git a/10-regular-expressions-javascript/9-regexp-groups/article.md b/11-regular-expressions-javascript/9-regexp-groups/article.md
similarity index 100%
rename from 10-regular-expressions-javascript/9-regexp-groups/article.md
rename to 11-regular-expressions-javascript/9-regexp-groups/article.md
diff --git a/10-regular-expressions-javascript/9-regexp-groups/regexp-nested-groups.svg b/11-regular-expressions-javascript/9-regexp-groups/regexp-nested-groups.svg
similarity index 100%
rename from 10-regular-expressions-javascript/9-regexp-groups/regexp-nested-groups.svg
rename to 11-regular-expressions-javascript/9-regexp-groups/regexp-nested-groups.svg
diff --git a/10-regular-expressions-javascript/index.md b/11-regular-expressions-javascript/index.md
similarity index 100%
rename from 10-regular-expressions-javascript/index.md
rename to 11-regular-expressions-javascript/index.md
diff --git a/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation-2.view/style.css b/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation-2.view/style.css
index 50a70357..61e19e36 100755
--- a/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation-2.view/style.css
+++ b/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation-2.view/style.css
@@ -1,7 +1,7 @@
 #text {
   display: block;
   height: 100px;
-  width: 400px;
+  width: 456px;
 }
 
 #table th {
diff --git a/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation.view/style.css b/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation.view/style.css
index 50a70357..61e19e36 100755
--- a/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation.view/style.css
+++ b/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseenter-mouseleave-delegation.view/style.css
@@ -1,7 +1,7 @@
 #text {
   display: block;
   height: 100px;
-  width: 400px;
+  width: 456px;
 }
 
 #table th {
diff --git a/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseleave-table.view/style.css b/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseleave-table.view/style.css
index 50a70357..61e19e36 100755
--- a/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseleave-table.view/style.css
+++ b/2-ui/3-event-details/3-mousemove-mouseover-mouseout-mouseenter-mouseleave/mouseleave-table.view/style.css
@@ -1,7 +1,7 @@
 #text {
   display: block;
   height: 100px;
-  width: 400px;
+  width: 456px;
 }
 
 #table th {
diff --git a/11-tools/1-tools-browser-extensions/article.md b/9-tools/1-tools-browser-extensions/article.md
similarity index 100%
rename from 11-tools/1-tools-browser-extensions/article.md
rename to 9-tools/1-tools-browser-extensions/article.md
diff --git a/11-tools/1-tools-browser-extensions/dnsflusher.png b/9-tools/1-tools-browser-extensions/dnsflusher.png
similarity index 100%
rename from 11-tools/1-tools-browser-extensions/dnsflusher.png
rename to 9-tools/1-tools-browser-extensions/dnsflusher.png
diff --git a/11-tools/1-tools-browser-extensions/downloadhelper.jpg b/9-tools/1-tools-browser-extensions/downloadhelper.jpg
similarity index 100%
rename from 11-tools/1-tools-browser-extensions/downloadhelper.jpg
rename to 9-tools/1-tools-browser-extensions/downloadhelper.jpg
diff --git a/11-tools/1-tools-browser-extensions/jsonview.png b/9-tools/1-tools-browser-extensions/jsonview.png
similarity index 100%
rename from 11-tools/1-tools-browser-extensions/jsonview.png
rename to 9-tools/1-tools-browser-extensions/jsonview.png
diff --git a/11-tools/1-tools-browser-extensions/pageinsight.png b/9-tools/1-tools-browser-extensions/pageinsight.png
similarity index 100%
rename from 11-tools/1-tools-browser-extensions/pageinsight.png
rename to 9-tools/1-tools-browser-extensions/pageinsight.png
diff --git a/11-tools/1-tools-browser-extensions/webdeveloper.png b/9-tools/1-tools-browser-extensions/webdeveloper.png
similarity index 100%
rename from 11-tools/1-tools-browser-extensions/webdeveloper.png
rename to 9-tools/1-tools-browser-extensions/webdeveloper.png
diff --git a/11-tools/2-fiddler/article.md b/9-tools/2-fiddler/article.md
similarity index 100%
rename from 11-tools/2-fiddler/article.md
rename to 9-tools/2-fiddler/article.md
diff --git a/11-tools/2-fiddler/fiddler-hook.png b/9-tools/2-fiddler/fiddler-hook.png
similarity index 100%
rename from 11-tools/2-fiddler/fiddler-hook.png
rename to 9-tools/2-fiddler/fiddler-hook.png
diff --git a/11-tools/2-fiddler/fiddler.png b/9-tools/2-fiddler/fiddler.png
similarity index 100%
rename from 11-tools/2-fiddler/fiddler.png
rename to 9-tools/2-fiddler/fiddler.png
diff --git a/11-tools/3-ie-http-analyzer/article.md b/9-tools/3-ie-http-analyzer/article.md
similarity index 100%
rename from 11-tools/3-ie-http-analyzer/article.md
rename to 9-tools/3-ie-http-analyzer/article.md
diff --git a/11-tools/3-ie-http-analyzer/ie-http-analyzer-2.gif b/9-tools/3-ie-http-analyzer/ie-http-analyzer-2.gif
similarity index 100%
rename from 11-tools/3-ie-http-analyzer/ie-http-analyzer-2.gif
rename to 9-tools/3-ie-http-analyzer/ie-http-analyzer-2.gif
diff --git a/11-tools/3-ie-http-analyzer/ie-http-analyzer-3.gif b/9-tools/3-ie-http-analyzer/ie-http-analyzer-3.gif
similarity index 100%
rename from 11-tools/3-ie-http-analyzer/ie-http-analyzer-3.gif
rename to 9-tools/3-ie-http-analyzer/ie-http-analyzer-3.gif
diff --git a/11-tools/3-ie-http-analyzer/ie-http-analyzer.gif b/9-tools/3-ie-http-analyzer/ie-http-analyzer.gif
similarity index 100%
rename from 11-tools/3-ie-http-analyzer/ie-http-analyzer.gif
rename to 9-tools/3-ie-http-analyzer/ie-http-analyzer.gif
diff --git a/11-tools/index.md b/9-tools/index.md
similarity index 100%
rename from 11-tools/index.md
rename to 9-tools/index.md