Hello there

Can anybody explain what remainder % is and where do we use them in java script?

Thanks

**Link to the challenge:**

https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-javascript/finding-a-remainder-in-javascript

Hello there

Can anybody explain what remainder % is and where do we use them in java script?

Thanks

**Link to the challenge:**

https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/basic-javascript/finding-a-remainder-in-javascript

Which step in the example do you not understand?

```
5 % 2 = 1 because
Math.floor(5 / 2) = 2 (Quotient)
2 * 2 = 4
5 - 4 = 1 (Remainder)
```

are you asking what does the word ‘remainder’ mean?

This a mathematics concept and not related to coding.

The remainder is the amount left when you divide two numbers together.

so 5 divided by 5 has zero remainder

but 5 divided by 4 has one remainder

Thanks for your reply ,trying to figure out how it works, give me some time to understand new to coding and did maths long time ago.

if your maths is not very good, I would strongly suggest reviewing grade school maths first before learning to code in javascript or any other language.

www.khanacademy.org is a good website (free) for learning grade school maths.

you can try some tests from different grade to see how much you remember.

Ok , i will have a look now.Thank you

So in remainder numbers left after division have to be even and odd,but not decimal number.

e.g 5/2=2.5 but we take 2 as a remainder?

remainder is never a decimal

5 divided by 2 gives a remainder of 1

here are five letters:

W W W W W

if you divide by 2 you split the letters like this

WW WW W

so only one W left without a second one therefore remainder is 1

hmm . i understand now ,thank you.

1 Like

It’s used to check what the integer remainder is when you try to divide one number by another.

If I divide 11 by 4:

11 - 4 is 7 (divides once)

7 - 4 is 3 (divides twice)

For it to divide further, I have to end up with 0, not a negative number.

3 - 4 is negative, so I can’t divide more than two times, remainder is 3.

A common use is to see if a number is even. If the number is even, there will be no remainder after dividing by 2.

```
> 10 % 2
0
```

So 10 - 2 is 8. 8 - 2 is 6. 6 - 2 is 4. 4 - 2 is 2. 2 - 2 is 0, it divides cleanly, remainder is 0.

```
> 11 % 2
1
```

So 11 - 2 is 9. 9 - 2 is 7. 7 - 2 is 5. 5 - 2 is 3. 3 - 2 is 1. Can’t subtract further, so remainder is 1.

So if I make a function:

```
function isEven(number) {
return number % 2 === 0
}
```

That’s saying “given a number, if I divide it by 2 and the remainder is 0, return true (it is even), but if the remainder is not 0, return false (number is not even)”

Really helpful, thanks

1 Like