Remember, a prime numbers can only be divided by itself and 1. You can use your knowledge of multiples (times tables) to eliminate numbers. Start with the smallest numbers and work your way up.

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 ...