The number 5 is prime because it only has the factors 1 and 5. To be a composite number for example 10 is a composite number because it has the factors 2, 5, 10, and 1. So for a number to be composite it has to have more than 1 and the factor. It has to be like the 10 that has 4 factors. For a number to be composite it should have 4 or more factors. Hope this helps. For a number to be prime it is supposed to have 2 factors.