﻿ Prime and Composite Numbers Worksheet | Problems & Solutions

Prime and Composite Numbers Worksheet

Prime and Composite Numbers Worksheet
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1.
Say whether the number 14 is prime or composite.
 a. composite b. prime

Solution:

The number 14 can be factorized as 1 × 14 and 2 × 7.

Its factors are 1, 2, 7, and 14.

The number 14 has more than two factors showing more than one rectangular array.

So, the number 14 is composite.

2.
Which of the following is not a composite number?
 a. 17 b. 12 c. 26 d. 22

Solution:

A composite number has more than two factors.

Factors of 26: 1, 2, 13 and 26
Factors of 22: 1, 2, 11 and 22
Factors of 17: 1 and 17
Factors of 12: 1, 2, 3, 4, 6, 12

The number 17 has exactly 2 factors, 1 and 17.

So, the number 17 is not a composite number.

3.
Identify the composite number.
 a. 113 b. 59 c. 71 d. 20

Solution:

A number that has more than two factors is called a composite number.

Factors of 59 = 1, 59

Factors of 71 = 1, 71

Factors of 113 = 1, 113

Factors of 20 = 1, 2, 4, 5, 10, 20.

Out of the given numbers, 20 is the only number that has more than two factors.

So, 20 is the composite number.

4.
Identify the composite number.
 a. 47 b. 53 c. 31 d. 32

Solution:

A number that has more than two factors is called a composite number.

Factors of 31 = 1, 31

Factors of 53 = 1, 53

Factors of 47 = 1, 47

Factors of 32 = 1, 2, 4, 8,16, 32

Out of the given numbers, 32 is the only number that has more than two factors.

So, 32 is the composite number.

5.
Identify the composite number.
 a. 36 b. 47 c. 13 d. 23

Solution:

A number that has more than two factors is called a composite number.

Factors of 23 = 1, 23

Factors of 13 = 1, 13

Factors of 47 = 1, 47

Factors of 36 = 1, 2, 3, 4, 6, 9, 12, 18, 36

Out of the given numbers, 36 is the only number that has more than two factors.

So, 36 is the composite number.

6.
Identify the composite number.
 a. 37 b. 29 c. 44 d. 17

Solution:

A composite number is a number which has at least one factor
other than 1 and itself.

In the given choices, 37, 17, and 29 are prime numbers.

44 has factors 1, 2, 4, 11, 22, and 44.

Thus, 44 has factors other than 1 and 44.

So, 44 is a composite number.

7.
Which of these is a composite number?
 a. 13 b. 41 c. 45 d. 37

Solution:

A composite number is a number which has at least one factor other than 1 and itself.

In the given choices, 13, 41, and 37 are prime numbers.

45 has factors 1, 3, 5, 9 15, and 45.

Thus, 45 has factors other than 1 and 45.

So, 45 is a composite number.

8.
Identify the prime number.
 a. 9 b. 29 c. 52 d. 34

Solution:

A number whose factors are 1 and the number itself, is called a prime number.

In the given choices, 9, 34, and 52 have factors other than 1 and itself.

Factors of 29 are 1 and 29.

So, 29 is a prime number.

9.
List all the prime numbers greater than 30 and less than 40.
 a. 31 and 37 b. 31, 37, and 39 c. 23 and 27 d. 17 and 19

Solution:

A number that has only two factors, one and itself is called a prime number.

List of prime numbers greater than 30 and less than 40 are 31 and 37.

10.
Which of these is not a prime number?
 a. 2 b. 14 c. 13 d. 17

Solution:

A prime number has exactly two factors, 1 and itself.

Factors of 17 : 1 and 17
Factors of 13 : 1 and 13
Factors of 2 : 1 and 2
Factors of 14 : 1, 2, 7, 14

The number 14 has more than 2 factors.

So, the number 14 is not a prime number.