Prime numbers

We have seen that two factors of any number are 1 and the number itself.

For example, 7 has the factors 1 and 7. Let’s try and find more factors of 7. We need to find numbers that result in whole numbers rather than fractions when we divide 7 by them.

7 ÷ 2 is a fraction

7 ÷ 3 is a fraction

7 ÷ 5 is a fraction

7 ÷ 6 is a fraction

The only factors of 7 are 1 and 7.

Numbers like 7, that only have 1 and the number itself as factors are called Prime Numbers.

The word prime comes from Latin and means first. When we look for the factors of a number, the first ones we find are 1 and the number itself. For prime numbers, there are no other factors.

The definition of a prime number is an integer greater than one that has only one and itself as positive factors.

The first five prime numbers are 2, 3, 5, 7 and 11.