In this tutorial, we will learn how to find **the average of the n ^{th} number of items** in an array using JavaScript.

There is no built-in JavaScript function to find the average of numbers. However, we can just write a function knowing the mathematical formula of finding the average of a given set of numbers.

**Mathematically**,

average = (sum of all the values) / number of values

Let’s say Jack received his report card and these are his marks:

English | Math | Biology | Chemistry | Physics |
---|---|---|---|---|

75 | 80 | 90 | 60 | 70 |

So the average of the marks will be:

```
average = (75 + 80 + 90 + 60 + 70) / 5 (five subjects)
average = 75
```

So, now let us write a JavaScript function to automate the process of finding the average easily.

The JavaScript function will take the **N** numbers of values of an array and it will return the average of the values.

```
function findAvg(arr){
let sumOfElement = 0;
let totalNumOfElement = arr.length;
arr.forEach(element =>{
sumOfElement += element
})
return average = sumOfElement/totalNumOfElement
}
console.log('Average:', findAvg([75,80,90,60,70]))
```

**Output:**

`Average: 75`

Here, in the above code:

`arr.length`

: gives us the total number of items.

we have used **forEach()** to loop through each item in the array and added the sum to the variable `sumOfElement`

.

In the end, we have divided the total sum of the items by the total number of items to get the average as the **return value**.

__Alternative Method:__

We can also use ** for** loop to do the same task as above.

```
function findAvg(arr){
let sumOfElement = 0;
let totalNumOfElement = arr.length;
for(i=0; i < totalNumOfElement;i++) {
sumOfElement += arr[i]
}
return average = sumOfElement/totalNumOfElement
}
console.log('Average:', findAvg([75,80,90,60,70])) // Average: 75
```

So, this is how you can pass N numbers of values as a parameter to the function to return the average in JavaScript.

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