Merge branch 'master' into patch-4

1-js/03-code-quality/01-debugging-chrome/article.md

@@ -101,7 +101,7 @@ Please open the informational dropdowns to the right (labeled with arrows). They
 
 1. **`Watch` -- shows current values for any expressions.**
 
-    You can click the plus `+` and input an expression. The debugger will shown its value at any moment, automatically recalculating it in in the process of execution.
+    You can click the plus `+` and input an expression. The debugger will show its value at any moment, automatically recalculating it in in the process of execution.
 
 2. **`Call Stack` -- shows the nested calls chain.**
 

1-js/05-data-types/03-string/article.md

@@ -236,7 +236,7 @@ alert( str.indexOf("id") ); // 1, "id" is found at the position 1 (..idget with
 
 The optional second parameter allows us to search starting from the given position.
 
-For instance, the first occurence of `"id"` is at position `1`. To look for the next occurence, let's start the search from  position `2`:
+For instance, the first occurence of `"id"` is at position `1`. To look for the next occurence, let's start the search from position `2`:
 
 ```js run
 let str = 'Widget with id';
@@ -245,7 +245,7 @@ alert( str.indexOf('id', 2) ) // 12
 ```
 
 
-If we're interested in all occurences, we can run `indexOf` in a loop. Every new call is made with the position after the previous match:
+If we're interested in all occurrences, we can run `indexOf` in a loop. Every new call is made with the position after the previous match:
 
 
 ```js run

1-js/05-data-types/05-array-methods/10-average-age/solution.md

@@ -1,6 +1,6 @@
 ```js run
 function getAverageAge(users) {
-  return arr.reduce((prev, user) => prev + user.age, 0) / arr.length;
+  return users.reduce((prev, user) => prev + user.age, 0) / users.length;
 }
 
 let john = { name: "John", age: 25 }