One arithmetic operator that we haven’t covered yet and may be less familiar is a modulo. A modulo returns a remainder, what is left over when we divide a number by another number.

4 % 3 = 1
4 % 2 = 0

The modulo is the same as the percentage symbol, but it’s important to remember it’s different meaning in this context.

Modulos are useful because they let us know if a number “fits” into a larger number, or if there will be a remainder. For example, how many eggs will be left over if I try and fit 56 eggs into crates of a dozen eggs?

int eggs = 56;
int crateAmount = 12;

int eggsLeftOver = eggs % crateAmount; 
Console.Write(eggsLeftOver); // prints 8

It can also be used to check if a number is odd or even. If a number is even, taking its modulo with 2 it will return a 0 and if it is odd it will return a 1:

int myNum = 85939824;
Console.Write(myNum % 2); // prints 0, so number is even