Prime numbers are those that only have two factors, the number itself and 1. The two factors cannot be the same. E.g. 2 is a prime number but 1 is not.A prime factor is when a prime number is a factor of another number e.g. 2 is a prime factor of 12. So when told to write a number as a product of its prime factors, you need to show all the prime numbers that can multiply together to make that particular number.So 40 as product of prime factors:2x2x2x5 or 2^3 x5 -----> diagram