Prime and Composite Numbers Worksheet

Prime and Composite Numbers Worksheet
  • Page 1
 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.


Correct answer : (1)
 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.


Correct answer : (1)
 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.


Correct answer : (4)
 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.


Correct answer : (4)
 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.


Correct answer : (1)
 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.


Correct answer : (3)
 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.


Correct answer : (3)
 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.


Correct answer : (2)
 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.


Correct answer : (1)
 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.


Correct answer : (2)

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