An amount left over after division, which happens when the first number does not divide exactly by the other.
Example: 19 cannot be divided exactly by 5.
The closest you can get without going over is 3 x 5 = 15, which is 4 less than 19.
So the remainder is 4
We write the answer of 19 ÷ 5 as "3 with a remainder of 4", which means that 19 divided by 5 has 3 equal parts but with 4 left over, and is usually written "3 R 4".
Play with it below, there will often be a remainder:
../numbers/images/divide-marbles.js