Remember that long division and remainders are discussed in Section 2.3. For every two numbers n and m, there are numbers q (for quotient) and r (for remainder) such that m=nq+r and 0 ≤ r ≤ n-1.

We say that a natural number A
**divides** a natural number B

- if B/A is natural, or equivalently
- if B can be divided by B with no remainder, or equivalently
- if there is a natural number C such that C·A=B.