Question

Is 25 a multiple of 2 or 5? How do you know?

Answer 1

`25` is a multiple of `5`. See Below for Explanation:
Also any multiple of `2` would be even but `25` is odd so `2` can not be a factor of `25`.

Explanation:

Simply list out the multiples of `2` and `5` first. See below:

Multiples of `5` include: `5`, `10`, `15`, `20`, `25`, `30`, `35`, and etc.

Multiples of `2` Include: `2`, `4`, `6`, `8`, `10`, `12`, `14`, `16`, `18`, `20`, `22`, `24`, `26` and etc.

As we can see, the multiples of `2` skip the number `25` so we can immediately assume that `25` is not a multiple of `2`. Therefore it must be a multiple of `5`.

And this makes sense right?

`5+5+5+5+5=25`.

`5^2=25`.

`5*5=25`.

Whatever way you want to think about it works.

Answer: `5`
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Foot note:

Any multiple of 2 is even. However 25 is odd so it can not be a multiple of 2.

Answer 2

From the last digit.

Explanation:

1. If the last digit is 0 or 5 then the number is divisible by 5.
2. if the last digit is 0,2,4,6,8 then the number is divisible by 2.

From 1 and 2 :

25 has last digit 5

=> 25 is divisible by 5

Answer 3

`25` is a multiple of only `5`, not `2` but see below for a better explanation.

Explanation:

Multiples of 5 always end with a `5` or a `0` and multiples of 2 always end with a even number or `0`.

Since `25` ends with `5`, it 25 is a multiple of 5!

My source is my mind.

I hope that helps you!

-Moksha