maths: Level 2

A prime number is a whole number greater than 1 whose only factors are 1 and itself.

The first few prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23 and 29.

Numbers that have more than two factors are called composite numbers.

 

 

1.      2 X 2 X 2
2.      3 X 5 X 5
3.      2 X 3 X 11
4.      2 X 5 X 7
5.      2 X 7 X 5

“Factors” are the numbers you multiply to get another number.

Some numbers have more than one factorization (more than one way of being factored).

For instance, 24 can be factored as :

1.      16
2.      35
3.      64
4.      66
5.      90

A factor that is a prime number.

In other words: any of the prime numbers that can be multiplied to give the original number.

Example: The prime factors of 15 are 3 and 5 (because 3×5=15, and 3 and 5 are prime numbers).

1.      144
2.      36
3.      64
4.      225
5.      121
6.      9

3.2 and 5.6

4.6 and 5.2

-6 and +4