Prime and Composite Numbers
To succeed on the GED, you'll need to know about factors and multiples. Factors are the numbers that can be multiplied together to make a given number (for example, 2 and 3 are factors of 6), while multiples are the products of multiplying a given number by other numbers (for example, 12 and 18 are multiples of 6). Before you can understand factors and multiples, though, you need to know the difference between prime and composite numbers.
A prime number cannot be divided evenly by any numbers other than itself and 1. For instance, the prime number 5 can only be divided evenly by 5 or 1: 5 ÷ 1 = 5 or 5 ÷ 5 = 1. Dividing 5 by any other number will result in a fraction or remainder, as for example 5 ÷ 4 = 1 ¼ or 5 ÷ 2 = 2 ½.
A composite number, on the other hand, can be divided evenly by some other number besides itself and 1. For example, 6 can be divided evenly by 3 and 2: 6 ÷ 3 = 2 and 6 ÷ 2 = 3.
This quiz will give you some useful practice with prime and composite numbers. Good luck!