freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-and-data-structures/basic-javascript/generate-random-whole-numbers-within-a-range.md

---
id: cf1111c1c12feddfaeb2bdef
title: Generate Random Whole Numbers within a Range
challengeType: 1
videoUrl: 'https://scrimba.com/c/cm83yu6'
forumTopicId: 18187
dashedName: generate-random-whole-numbers-within-a-range
---

# --description--

Instead of generating a random whole number between zero and a given number like we did before, we can generate a random whole number that falls within a range of two specific numbers.

To do this, we'll define a minimum number `min` and a maximum number `max`.

Here's the formula we'll use. Take a moment to read it and try to understand what this code is doing:

`Math.floor(Math.random() * (max - min + 1)) + min`

# --instructions--

Create a function called `randomRange` that takes a range `myMin` and `myMax` and returns a random whole number that's greater than or equal to `myMin`, and is less than or equal to `myMax`, inclusive.

# --hints--

The lowest random number that can be generated by `randomRange` should be equal to your minimum number, `myMin`.

```js
assert(calcMin === 5);
```

The highest random number that can be generated by `randomRange` should be equal to your maximum number, `myMax`.

```js
assert(calcMax === 15);
```

The random number generated by `randomRange` should be an integer, not a decimal.

```js
assert(randomRange(0, 1) % 1 === 0);
```

`randomRange` should use both `myMax` and `myMin`, and return a random number in your range.

```js
assert(
  (function () {
    if (
      code.match(/myMax/g).length > 1 &&
      code.match(/myMin/g).length > 2 &&
      code.match(/Math.floor/g) &&
      code.match(/Math.random/g)
    ) {
      return true;
    } else {
      return false;
    }
  })()
);
```

# --seed--

## --after-user-code--

```js
var calcMin = 100;
var calcMax = -100;
for(var i = 0; i < 100; i++) {
  var result = randomRange(5,15);
  calcMin = Math.min(calcMin, result);
  calcMax = Math.max(calcMax, result);
}
(function(){
  if(typeof myRandom === 'number') {
    return "myRandom = " + myRandom;
  } else {
    return "myRandom undefined";
  }
})()
```

## --seed-contents--

```js
function randomRange(myMin, myMax) {
  // Only change code below this line
  return 0;
  // Only change code above this line
}
```

# --solutions--

```js
function randomRange(myMin, myMax) {
  return Math.floor(Math.random() * (myMax - myMin + 1)) + myMin;
}
```