freeCodeCamp/guide/english/certifications/javascript-algorithms-and-data-structures/intermediate-algorithm-scripting/sum-all-numbers-in-a-range/index.md

---
title: Sum All Numbers in a Range
---
![:triangular_flag_on_post:](https://forum.freecodecamp.com/images/emoji/emoji_one/triangular_flag_on_post.png?v=3 ":triangular_flag_on_post:") Remember to use <a>**`Read-Search-Ask`**</a> if you get stuck. Try to pair program ![:busts_in_silhouette:](https://forum.freecodecamp.com/images/emoji/emoji_one/busts_in_silhouette.png?v=3 ":busts_in_silhouette:") and write your own code ![:pencil:](https://forum.freecodecamp.com/images/emoji/emoji_one/pencil.png?v=3 ":pencil:")

### ![:checkered_flag:](https://forum.freecodecamp.com/images/emoji/emoji_one/checkered_flag.png?v=3 ":checkered_flag:") Problem Explanation:

You need to create a program that will take an array of two numbers who are not necessarily in order, and then add not just those numbers but any numbers in between. For example, [3,1] will be the same as `1+2+3` and not just `3+1`

## ![:speech_balloon:](https://forum.freecodecamp.com/images/emoji/emoji_one/speech_balloon.png?v=3 ":speech_balloon:") Hint: 1

Use `Math.max()` to find the maximum value of two numbers.

> _try to solve the problem now_

## ![:speech_balloon:](https://forum.freecodecamp.com/images/emoji/emoji_one/speech_balloon.png?v=3 ":speech_balloon:") Hint: 2

Use `Math.min()` to find the minimum value of two numbers.

> _try to solve the problem now_

## ![:speech_balloon:](https://forum.freecodecamp.com/images/emoji/emoji_one/speech_balloon.png?v=3 ":speech_balloon:") Hint: 3

Remember to that you must add all the numbers in between so this would require a way to get those numbers.

> _try to solve the problem now_

## Spoiler Alert!

![warning sign](//discourse-user-assets.s3.amazonaws.com/original/2X/2/2d6c412a50797771301e7ceabd554cef4edcd74d.gif)

**Solution ahead!**

## ![:beginner:](https://forum.freecodecamp.com/images/emoji/emoji_one/beginner.png?v=3 ":beginner:") Basic Code Solution:

    function sumAll(arr) {
        var max = Math.max(arr[0], arr[1]);
        var min = Math.min(arr[0], arr[1]);
        var temp = 0;
        for (var i=min; i <= max; i++){
            temp += i;
        }
      return(temp);
    }

    sumAll([1, 4]);

![:rocket:](https://forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=3 ":rocket:") <a href='https://repl.it/CLm6/0' target='_blank' rel='nofollow'>Run Code</a>

### Code Explanation:

*   First create a variable to store the max number between two.
*   The same as before for the Smallest number.
*   We create a temporary variable to add the numbers.

Since the numbers might not be always in order, using `max()` and `min()` will help organize.

#### Relevant Links

*   <a href='http://forum.freecodecamp.com/t/javascript-math-max/14682' target='_blank' rel='nofollow'>Math.max()</a>
*   <a href='http://forum.freecodecamp.com/t/javascript-math-min/14684' target='_blank' rel='nofollow'>Math.min()</a>
*   <a href='http://forum.freecodecamp.com/t/javascript-for-loop/14666' target='_blank' rel='nofollow'>For Loops</a>

## ![:sunflower:](https://forum.freecodecamp.com/images/emoji/emoji_one/sunflower.png?v=3 ":sunflower:") Intermediate Code Solution:

    const sumAll = (arr) => {
      // Buckle up everything to one!
      const startNum = arr[0];
      const endNum = arr[1];
      
      // Get the count of numbers between the two numbers by subtracting them and add 1 to the absolute value.
      // ex. There are |1-4| + 1 = 4, (1, 2, 3, 4), 4 numbers between 1 and 4.
      const numCount = Math.abs(startNum - endNum) + 1
      
      // Using Arithmetic Progression summing formula
      const sum = (startNum + endNum) * numCount / 2;
      return sum;
    };

![:rocket:](https://forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=3 ":rocket:") <a href='https://repl.it/CLm7/0' target='_blank' rel='nofollow'>Run Code</a>

### Code Explanation:

*   The formula for calculating the sum of a continuous range is "(startNum + endNum) * numCount / 2".
*   arr[0] and arr[1] can either be startNum or endNum, order doesn't matter.
*   We can get the count of numbers in range by "Math.abs(arr[0] - arr[1]) + 1".
*   Applying the formula by plugging in the numbers.

#### Relevant Links

*   <a href='http://forum.freecodecamp.com/t/javascript-array-prototype-sort/14306' target='_blank' rel='nofollow'>Array.sort()</a>
*   <a href='https://en.wikipedia.org/wiki/Arithmetic_progression#Sum' target='_blank' rel='nofollow'>Arithmetic Progression summing formula</a>
*   <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions' target='_blank' rel='nofollow'>ES6 arrow function</a>

## ![:rotating_light:](https://forum.freecodecamp.com/images/emoji/emoji_one/rotating_light.png?v=3 ":rotating_light:") Advanced Code Solution:

    function sumAll(arr) {
        var sum = 0;
        for (var i = Math.min(...arr); i <= Math.max(...arr); i++){
            sum += i;
        }
      return sum;
    }

    sumAll([1, 4]);

![:rocket:](https://forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=3 ":rocket:") <a href='https://repl.it/CLm8/0' target='_blank' rel='nofollow'>Run Code</a>

### Code Explanation:

*   Creating a variable sum to store the sum of the elements.
*   Starting iteration of the loop from min element of given array and stopping when it reaches the max element.
*   Using a spread operator (...arr) allows passing the actual array to the function instead of one-by-one elements.

#### Relevant Links

*   <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator' target='_blank' rel='nofollow'>Spread Operator</a>
*   <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/max' target='_blank' rel='nofollow'>Using Spread Operator in Math.max()</a>

## ![:clipboard:](https://forum.freecodecamp.com/images/emoji/emoji_one/clipboard.png?v=3 ":clipboard:") NOTES FOR CONTRIBUTIONS:

*   ![:warning:](https://forum.freecodecamp.com/images/emoji/emoji_one/warning.png?v=3 ":warning:") **DO NOT** add solutions that are similar to any existing solutions. If you think it is **_similar but better_**, then try to merge (or replace) the existing similar solution.
*   Add an explanation of your solution.
*   Categorize the solution in one of the following categories — **Basic**, **Intermediate** and **Advanced**. ![:traffic_light:](https://forum.freecodecamp.com/images/emoji/emoji_one/traffic_light.png?v=3 ":traffic_light:")