diff --git a/1-js/02-first-steps/06-alert-prompt-confirm/1-simple-page/solution.md b/1-js/02-first-steps/06-alert-prompt-confirm/1-simple-page/solution.md
@@ -1,8 +1,8 @@
JavaScript-code:

-```js demo run
-let name = prompt("What is your name?", "");
-alert(name);
```

The full page:
@@ -15,8 +15,8 @@ The full page:
  <script>
    'use strict';

-    let name = prompt("What is your name?", "");
-    alert(name);
  </script>

</body>

diff --git a/1-js/02-first-steps/13-while-for/1-loop-last-value/solution.md b/1-js/02-first-steps/13-while-for/1-loop-last-value/solution.md
@@ -1,25 +1,25 @@
-The answer: `1`.

-```js run
let i = 3;

while (i) {
  alert( i-- );
}
```

-Every loop iteration decreases `i` by `1`. The check `while(i)` stops the loop when `i = 0`.

-Hence, the steps of the loop form the following sequence ("loop unrolled"):

```js
let i = 3;

-alert(i--); // shows 3, decreases i to 2

-alert(i--) // shows 2, decreases i to 1

-alert(i--) // shows 1, decreases i to 0

-// done, while(i) check stops the loop
```
diff --git a/1-js/02-first-steps/13-while-for/1-loop-last-value/task.md b/1-js/02-first-steps/13-while-for/1-loop-last-value/task.md
@@ -2,9 +2,9 @@ importance: 3

---

-# Last loop value

-What is the last value alerted by this code? Why?

```js
let i = 3;

diff --git a/1-js/02-first-steps/13-while-for/2-which-value-while/task.md b/1-js/02-first-steps/13-while-for/2-which-value-while/task.md
@@ -2,21 +2,21 @@ importance: 4

---

-# Which values does the while loop show?

-For every loop iteration, write down which value it outputs and then compare it with the solution.

-Both loops `alert` the same values, or not?

-1. The prefix form `++i`:

-    ```js
-    let i = 0;
-    while (++i < 5) alert( i );
-    ```
-2. The postfix form `i++`

-    ```js
-    let i = 0;
-    while (i++ < 5) alert( i );
-    ```
diff --git a/1-js/02-first-steps/13-while-for/3-which-value-for/solution.md b/1-js/02-first-steps/13-while-for/3-which-value-for/solution.md
@@ -1,17 +1,17 @@
-**The answer: from `0` to `4` in both cases.**

-```js run
for (let i = 0; i < 5; ++i) alert( i );

for (let i = 0; i < 5; i++) alert( i );
```

-That can be easily deducted from the algorithm of `for`:

-1. Execute once `i = 0` before everything (begin).
-2. Check the condition `i < 5`
-3. If `true` -- execute the loop body `alert(i)`, and then `i++`

-The increment `i++` is separated from the condition check (2). That's just another statement.

-The value returned by the increment is not used here, so there's no difference between `i++` and `++i`.
diff --git a/1-js/02-first-steps/13-while-for/3-which-value-for/task.md b/1-js/02-first-steps/13-while-for/3-which-value-for/task.md
@@ -2,19 +2,19 @@ importance: 4

---

-# Which values get shown by the "for" loop?

-For each loop write down which values it is going to show. Then compare with the answer.

-Both loops `alert` same values or not?

-1. The postfix form:

-    ```js
-    for (let i = 0; i < 5; i++) alert( i );
-    ```
-2. The prefix form:

-    ```js
-    for (let i = 0; i < 5; ++i) alert( i );
-    ```
diff --git a/1-js/02-first-steps/13-while-for/4-for-even/solution.md b/1-js/02-first-steps/13-while-for/4-for-even/solution.md
@@ -1,11 +1,9 @@
-
-
-```js run demo
for (let i = 2; i <= 10; i++) {
  if (i % 2 == 0) {
    alert( i );
  }
}
```

-We use the "modulo" operator `%` to get the remainder and check for the evenness here.
-Original file line number
+Diff line change
@@ Expand Up / @@ -2,9 +2,9 @@ importance: 3 @@
     ---
-    # Last loop value
-    What is the last value alerted by this code? Why?
     ```js
     let i = 3;
@@ Expand Down @@