Work Step by Step
Numbers can only be one or the other. Prime numbers are numbers only divisible by 1 and itself. It cannot be composite because there are no other numbers by which it can be divided. Composite numbers can be divided by something besides 1 and itself, meaning 1 and itself aren't its only factors. For example: 7 can only be divided by 1 and 7, making it prime. There are no other numbers by which to divide it, so it can't be composite. 9 can be divided by 1, 3, and 9, making it composite. 1 and 9 aren't the only factors because one can divide 9 by 3, so it can't be prime.