Question

Can a prime number be a multiple of any other number except itself. Explain why or why not

Answer 1

No, by definition a prime number is one where the only factors are 1 and itself. If some prime number is a multiple of another number, then that other number is a factor of the prime number. But that would make it composite (non-prime)

For example, the number 11 is prime. The only factors are 1 and itself. If we made the claim that 11 is a multiple of 2, then 2 would be a factor of 11 making 11 non-prime (as it doesn't just have 1 and itself as factors).

Note: If you have two numbers A and B, and you say that A is a factor of B, then A is the smaller value. Though there is the exception when A = B. For example, saying "8 is a factor of 16" has 8 being the smaller value.

Another note: if you say "A is a multiple of B", then B is larger than A. The exception is when A = B. Example: "100 is a multiple of 5"