[Guide] Basic JS: Random numbers within range. Enhancements (#19539)

* [Guide] Basic JS: Random numbers within range. Enhancements

Added code solution, explanation, resources and other minor fixes.

* Additional fix; list.

* update: created ordered list of calculation

guide/english/certifications/javascript-algorithms-and-data-structures/basic-javascript/generate-random-whole-numbers-within-a-range/index.md

@@ -3,7 +3,49 @@ title: Generate Random Whole Numbers within a Range
 ---
 ## Generate Random Whole Numbers within a Range
 
-**Help for passing the final test:**
-*`randomRange` should use both `myMax` and `myMin`, and return a random number in your range.*
 
-You cannot pass the final test if you are only re-using the function `ourRandomRange` inside your `randomRange` formula. You need to write your own formula that uses the variables `myMax` and `myMin`. It will do the same job as using `ourRandomRange`, but ensures that you have understood the principles of the `Math.floor()` and `Math.random()` functions.
+### Problem explanation:
+_Create a function called `randomRange` that takes a range `myMin` and `myMax`and returns a random number that's greater than or equal to `myMin`, and is less than or equal to `myMax`, inclusive._
+
+#### Hint 1
+`randomRange` should use both `myMax` and `myMin`, and return a random number in your range.
+
+You cannot pass the test if you are only re-using the function `ourRandomRange` inside your `randomRange` formula. You need to write your own formula that uses the variables `myMax` and `myMin`. It will do the same job as using `ourRandomRange`, but ensures that you have understood the principles of the `Math.floor()` and `Math.random()` functions.
+> _try to solve the problem now_
+
+
+## Spoiler alert!
+
+**Solution ahead!**
+
+## Basic code solution:
+
+```javascript
+function randomRange(myMin, myMax) {
+
+  return Math.floor(Math.random() * (myMax - myMin + 1) + myMin);
+
+}
+```
+·  Run code at [repl.it](https://repl.it/@AdrianSkar/Basic-JS-Random-whole-numbers-within-range).
+
+### Code explanation
+- `Math.random()` generates our random number between 0 and ≈ 0.9.
+- Before multiplying it, it resolves the part between parenthesis `(myMax - myMin + 1)` because of the grouping operator `(   )`.
+- The result of that multiplication is followed by adding `myMin` and then "rounded" to the largest integer less than or equal to it (eg: 9.9 would result in 9)
+
+If the values were `myMin = 1, myMax= 10`, one result could be the following:
+ 1. `Math.random() = 0.8244326990411024`
+ 2. `(myMax - myMin + 1) = 10 - 1 + 1 -> 10`
+ 3. `a * b =  8.244326990411024`
+ 4. `c + myMin = 9.244326990411024`
+ 5. `Math.floor(9.244326990411024) = 9`
+
+
+### Resources
+
+- ["Math.random()" - *MDN JavaScript reference*](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random)
+- ["Math.floor()" - *MDN JavaScript reference*](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/floor)
+- ["Grouping operator" - *MDN JavaScript reference*](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Grouping)
+
+