What is a Composite Number
Composite numbers are numbers divisible by one or more numbers other than 1 and itself.
In other words, we can say that numbers having more than two factors are composite numbers.
For Example – 4, 6, 8, 9, 10, 12, 14, 15, 16, 18 are Composite numbers
Which of the following numbers are Composite Numbers ?
Example 1
8, 2, 7
Solution
Factors of 8 are 2 x 2 x 2 x 1
Factors of 2 are 2 x 1
Factors of 7 are 7 x 1
Here, Factors of 8 are 2 x 2 x 2 x 1
8 is divisible by 1, 2, 4, 8
Therefore, 8 is a composite number.
Example 2
12, 11, 5
Solution
Factors of 12 are 2 x 2 x 3 x 1
Factors of 11 are 11 x 1
Factors of 5 are 5 x 1
Here, Factors of 12 are 2 x 2 x 3 x 1
12 is divisible by 1, 2, 4, 6, 12
Therefore, 12 is a composite number.
Example 3
17, 7, 14
Solution
Factors of 14 are 2 x 7 x 1
Factors of 7 are 7 x 1
Factors of 17 are 17 x 1
Here, Factors of 14 are 2 x 7 x 1
14 is divisible by 2 , 7 , 14 , 1
Therefore, 14 is composite number.
Example 4
28, 11, 13
Solution
Factors of 28 are 2 x 7 x 2 x 1
Factors of 11 are 11 x 1
Factors of 13 are 13 x 1
Here, Factors of 28 are 2 x 7 x 2 x 1
28 is divisible by 2 , 7 , 14 , 28 , 1
Therefore, 28 is composite number.
Example 5
5, 21, 13
Solution
Factors of 21 are 3 x 7 x 1
Factors of 5 are 5 x 1
Factors of 13 are 13 x 1
Here, Factors of 21 are 3 x 7
21 is divisible by 3 , 7 , 21 , 1
Therefore, 21 is composite number.