One of the uses of *Modulus* is to detect if a number is even or odd.

If a number is evenly divisible by 2 leaving a remainder of zero then the number is even.

If the number is not evenly divisible by 2 and leaves a remainder of 1 then it is an odd number.

For example when dividing numbers say 8 and 2 results in a remainer of 0

So 8 is an even number.

While dividing numbers 7 and 2, results in a remainder of 1

So 7 is an odd number.

## Example

Find all student ids which are even.