Find HCF of 3 Numbers by using Prime Factorization

Name Grade School
Date Questions20 Score

1
Find the GCF of 12, 15 and 18
2
Find the GCF of 8, 10 and 12
3
Find the GCF of 9, 12 and 18
4
Find the GCF of 8, 12 and 16
5
Find the GCF of 12, 15 and 20
6
Find the GCF of 18, 24 and 36
7
Find the GCF of 6, 9 and 12
8
Find the GCF of 15, 20 and 25
9
Find the GCF of 6, 10 and 12
10
Find the GCF of 12, 16 and 18
11
Find the GCF of 20, 25 and 30
12
Find the GCF of 12, 14 and 16
13
Find the GCF of 24, 36 and 40
14
Find the GCF of 10, 12 and 14
15
Find the GCF of 30, 45 and 60
16
Find the GCF of 4, 10 and 12
17
Find the GCF of 12, 16 and 20
18
Find the GCF of 18, 24 and 32
19
Find the GCF of 10, 12 and 15
20
Find the GCF of 8, 12 and 18

Answers Key
1
Find the GCF of 12, 15 and 18
3 is the GCF of 12, 15 and 18
Factors of 12
212
26
33
1
Factors of 15
315
55
1
Factors of 18
218
39
33
1


Factors of 12 = 2 x 2 x 3
Factors of 15 = 3 x 5
Factors of 18 = 2 x 3 x 3
Multiply all the common factors of 12, 15 and 18.
3 = 3
GCF(12, 15, 18) = 3
2
Find the GCF of 8, 10 and 12
2 is the GCF of 8, 10 and 12
Factors of 8
28
24
22
1
Factors of 10
210
55
1
Factors of 12
212
26
33
1


Factors of 8 = 2 x 2 x 2
Factors of 10 = 2 x 5
Factors of 12 = 2 x 2 x 3
Multiply all the common factors of 8, 10 and 12.
2 = 2
GCF(8, 10, 12) = 2
3
Find the GCF of 9, 12 and 18
3 is the GCF of 9, 12 and 18
Factors of 9
39
33
1
Factors of 12
212
26
33
1
Factors of 18
218
39
33
1


Factors of 9 = 3 x 3
Factors of 12 = 2 x 2 x 3
Factors of 18 = 2 x 3 x 3
Multiply all the common factors of 9, 12 and 18.
3 = 3
GCF(9, 12, 18) = 3
4
Find the GCF of 8, 12 and 16
4 is the GCF of 8, 12 and 16
Factors of 8
28
24
22
1
Factors of 12
212
26
33
1
Factors of 16
216
28
24
22
1


Factors of 8 = 2 x 2 x 2
Factors of 12 = 2 x 2 x 3
Factors of 16 = 2 x 2 x 2 x 2
Multiply all the common factors of 8, 12 and 16.
2 x 2 = 4
GCF(8, 12, 16) = 4
5
Find the GCF of 12, 15 and 20
1 is the GCF of 12, 15 and 20
Factors of 12
212
26
33
1
Factors of 15
315
55
1
Factors of 20
220
210
55
1


Factors of 12 = 2 x 2 x 3
Factors of 15 = 3 x 5
Factors of 20 = 2 x 2 x 5
Multiply all the common factors of 12, 15 and 20.
1 = 1
GCF(12, 15, 20) = 1
6
Find the GCF of 18, 24 and 36
6 is the GCF of 18, 24 and 36
Factors of 18
218
39
33
1
Factors of 24
224
212
26
33
1
Factors of 36
236
218
39
33
1


Factors of 18 = 2 x 3 x 3
Factors of 24 = 2 x 2 x 2 x 3
Factors of 36 = 2 x 2 x 3 x 3
Multiply all the common factors of 18, 24 and 36.
2 x 3 = 6
GCF(18, 24, 36) = 6
7
Find the GCF of 6, 9 and 12
3 is the GCF of 6, 9 and 12
Factors of 6
26
33
1
Factors of 9
39
33
1
Factors of 12
212
26
33
1


Factors of 6 = 2 x 3
Factors of 9 = 3 x 3
Factors of 12 = 2 x 2 x 3
Multiply all the common factors of 6, 9 and 12.
3 = 3
GCF(6, 9, 12) = 3
8
Find the GCF of 15, 20 and 25
5 is the GCF of 15, 20 and 25
Factors of 15
315
55
1
Factors of 20
220
210
55
1
Factors of 25
525
55
1


Factors of 15 = 3 x 5
Factors of 20 = 2 x 2 x 5
Factors of 25 = 5 x 5
Multiply all the common factors of 15, 20 and 25.
5 = 5
GCF(15, 20, 25) = 5
9
Find the GCF of 6, 10 and 12
2 is the GCF of 6, 10 and 12
Factors of 6
26
33
1
Factors of 10
210
55
1
Factors of 12
212
26
33
1


Factors of 6 = 2 x 3
Factors of 10 = 2 x 5
Factors of 12 = 2 x 2 x 3
Multiply all the common factors of 6, 10 and 12.
2 = 2
GCF(6, 10, 12) = 2
10
Find the GCF of 12, 16 and 18
2 is the GCF of 12, 16 and 18
Factors of 12
212
26
33
1
Factors of 16
216
28
24
22
1
Factors of 18
218
39
33
1


Factors of 12 = 2 x 2 x 3
Factors of 16 = 2 x 2 x 2 x 2
Factors of 18 = 2 x 3 x 3
Multiply all the common factors of 12, 16 and 18.
2 = 2
GCF(12, 16, 18) = 2
11
Find the GCF of 20, 25 and 30
5 is the GCF of 20, 25 and 30
Factors of 20
220
210
55
1
Factors of 25
525
55
1
Factors of 30
230
315
55
1


Factors of 20 = 2 x 2 x 5
Factors of 25 = 5 x 5
Factors of 30 = 2 x 3 x 5
Multiply all the common factors of 20, 25 and 30.
5 = 5
GCF(20, 25, 30) = 5
12
Find the GCF of 12, 14 and 16
2 is the GCF of 12, 14 and 16
Factors of 12
212
26
33
1
Factors of 14
214
77
1
Factors of 16
216
28
24
22
1


Factors of 12 = 2 x 2 x 3
Factors of 14 = 2 x 7
Factors of 16 = 2 x 2 x 2 x 2
Multiply all the common factors of 12, 14 and 16.
2 = 2
GCF(12, 14, 16) = 2
13
Find the GCF of 24, 36 and 40
4 is the GCF of 24, 36 and 40
Factors of 24
224
212
26
33
1
Factors of 36
236
218
39
33
1
Factors of 40
240
220
210
55
1


Factors of 24 = 2 x 2 x 2 x 3
Factors of 36 = 2 x 2 x 3 x 3
Factors of 40 = 2 x 2 x 2 x 5
Multiply all the common factors of 24, 36 and 40.
2 x 2 = 4
GCF(24, 36, 40) = 4
14
Find the GCF of 10, 12 and 14
2 is the GCF of 10, 12 and 14
Factors of 10
210
55
1
Factors of 12
212
26
33
1
Factors of 14
214
77
1


Factors of 10 = 2 x 5
Factors of 12 = 2 x 2 x 3
Factors of 14 = 2 x 7
Multiply all the common factors of 10, 12 and 14.
2 = 2
GCF(10, 12, 14) = 2
15
Find the GCF of 30, 45 and 60
15 is the GCF of 30, 45 and 60
Factors of 30
230
315
55
1
Factors of 45
345
315
55
1
Factors of 60
260
230
315
55
1


Factors of 30 = 2 x 3 x 5
Factors of 45 = 3 x 3 x 5
Factors of 60 = 2 x 2 x 3 x 5
Multiply all the common factors of 30, 45 and 60.
3 x 5 = 15
GCF(30, 45, 60) = 15
16
Find the GCF of 4, 10 and 12
2 is the GCF of 4, 10 and 12
Factors of 4
24
22
1
Factors of 10
210
55
1
Factors of 12
212
26
33
1


Factors of 4 = 2 x 2
Factors of 10 = 2 x 5
Factors of 12 = 2 x 2 x 3
Multiply all the common factors of 4, 10 and 12.
2 = 2
GCF(4, 10, 12) = 2
17
Find the GCF of 12, 16 and 20
4 is the GCF of 12, 16 and 20
Factors of 12
212
26
33
1
Factors of 16
216
28
24
22
1
Factors of 20
220
210
55
1


Factors of 12 = 2 x 2 x 3
Factors of 16 = 2 x 2 x 2 x 2
Factors of 20 = 2 x 2 x 5
Multiply all the common factors of 12, 16 and 20.
2 x 2 = 4
GCF(12, 16, 20) = 4
18
Find the GCF of 18, 24 and 32
2 is the GCF of 18, 24 and 32
Factors of 18
218
39
33
1
Factors of 24
224
212
26
33
1
Factors of 32
232
216
28
24
22
1


Factors of 18 = 2 x 3 x 3
Factors of 24 = 2 x 2 x 2 x 3
Factors of 32 = 2 x 2 x 2 x 2 x 2
Multiply all the common factors of 18, 24 and 32.
2 = 2
GCF(18, 24, 32) = 2
19
Find the GCF of 10, 12 and 15
1 is the GCF of 10, 12 and 15
Factors of 10
210
55
1
Factors of 12
212
26
33
1
Factors of 15
315
55
1


Factors of 10 = 2 x 5
Factors of 12 = 2 x 2 x 3
Factors of 15 = 3 x 5
Multiply all the common factors of 10, 12 and 15.
1 = 1
GCF(10, 12, 15) = 1
20
Find the GCF of 8, 12 and 18
2 is the GCF of 8, 12 and 18
Factors of 8
28
24
22
1
Factors of 12
212
26
33
1
Factors of 18
218
39
33
1


Factors of 8 = 2 x 2 x 2
Factors of 12 = 2 x 2 x 3
Factors of 18 = 2 x 3 x 3
Multiply all the common factors of 8, 12 and 18.
2 = 2
GCF(8, 12, 18) = 2

Find Highest Common Factor (HCF) Worksheets

Find HCF of three numbers worksheet with answers to practice & learn 6th grade math problems on highest common factor is available online for free in printable & downloadable (pdf & image) format. Tap on PRINT, PDF or IMAGE button to print or download this grade-6 worksheet to practice how to find the HCF for 3 numbers by using prime factorization.

How to Use this Worksheet

In this sixth grade math worksheet, students are required to find the HCF (Highest or Greatest Common factor) of three given numbers by using prime factorization. To find the prime factors of a number, use special division method as like as the step by step work given in the answer key. The product of common prime factors of 3 given numbers is the Greatest Common Factor.

Answers Key

Teachers, tutors, parents or students can check or validate the solved math workbook of 6th grade math questions on writing HCF of 3 given numbers by using the corresponding answers key which comprises the step by step work for each problem in the worksheet.

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