What are prime numbers?

Numbers which have only 2 different factors. You should not confuse prime numbers with odd numbers.

The following are prime number:

2,3,5,,7,11,13

2×1=2

3×1=3

5×1=5

7×1=7

11×1=11

13×1=13

 

All these numbers have only 2 different factors. 1 and the number itself

 

9 is not a prime number because it has 3 factors

1×9=9

3×3=9

 

The factors of 9 are 1,3,9