Prime numbers are special numbers, greater than 1, that have exactly two factors, themselves and 1. 19 is a prime number. It can only be divided by 1 and 19. 9 is not a prime number. It can be ...

as 2 is not a factor of 75. We now try to divide by the next largest prime number which is 3: We can no longer divide by 3, as 3 is not a factor of 25. We must again look for a larger prime number ...