minor fixes

1-js/04-object-basics/07-optional-chaining/article.md

@@ -135,7 +135,7 @@ For instance:
 let user = null;
 let x = 0;
 
-user?.sayHi(x++); // no "sayHi", so the execution doesn't reach x++
+user?.sayHi(x++); // no "user", so the execution doesn't reach sayHi call and x++
 
 alert(x); // 0, value not incremented
 ```

1-js/05-data-types/02-number/article.md

@@ -47,7 +47,7 @@ Now let's write something very small. Say, 1 microsecond (one millionth of a sec
 let mсs = 0.000001;
 ```
 
-Just like before, using `"e"` can help. If we'd like to avoid writing the zeroes explicitly, we could say the same as:
+Just like before, using `"e"` can help. If we'd like to avoid writing the zeroes explicitly, we could write the same as:
 
 ```js
 let mcs = 1e-6; // six zeroes to the left from 1