At the end of this lesson, students should be able to identity prime and composite numbers.

PRIME NUMBERS

A prime number has only two factors, the number 1 and itself. The factors are the digits that will multiply to get the number in question.

Examples are 2, 3, 5, 7, 11, 13, 17, 19 . . .

Note that all these numbers are only divisible by 1 and themselves.

2 has two factors; 2 x 1 = 2

The factors are 1 and 2

Therefore 2 is a prime number. 2 IS THE ONLY EVEN NUMBER THAT IS ALSO A PRIME NUMBER.

COMPOSITE NUMBERS

Composite numbers are numbers that have more than two factors. Prime numbers have only two factors whiles composite numbers have more than two factors. Examples are 6, 8, 9, 10, 12, 14…

6×1=6, 2×3=6 therefore, the factors of 6 are {1, 2, 3 and 6}

12×1=12, 6×2=12, 3×4=12. The factors of twelve are {1, 2, 3, 4, 6, and 12}

NOTE

ALL EVEN NUMBERS APART FROM 2 ARE ALL COMPOSITE NUMBERS.