**Tell us what’s happening:**

Could someone please explain to me, in the most simple and non-mathematical terms, what this sentence means; " Write a recursive function, `sum(arr, n)`

, **that returns the sum of the elements from 0 to n inclusive in an array arr .** Hints:

`sum([1], 0)`

should equal 1, `sum([2, 3, 4], 1)`

should equal 5.I’m not looking for an explanation of recursion or how for-loops work. I’m looking for a simple explanation of the mathematical process going on in the highlighted section **that returns the sum of the elements from 0 to n inclusive in an array arr .** Pretty simple sentence really but I’m native English and this makes no sense to me, it has been many many years since I was taught basic maths.

**Your code so far**

```
function sum(arr, n) {
// Only change code below this line
// Only change code above this line
}
```

**Your browser information:**

User Agent is: `Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.87 Safari/537.36`

.

**Challenge:** Replace Loops using Recursion

**Link to the challenge:**

https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/basic-javascript/replace-loops-using-recursion