# Spectrum Math Grade 6 Chapter 1 Lesson 7 Answer Key Greatest Common Factor

Go through the Spectrum Math Grade 6 Answer Key Chapter 1 Lesson 1.7 Greatest Common Factor and get the proper assistance needed during your homework.

## Spectrum Math Grade 6 Chapter 1 Lesson 1.7 Greatest Common Factor Answers Key

A factor is a divisor of a number. (For example, 3 and 4 are both factors of 12.) A common factor is a divisor that is shared by two or more numbers (1, 2, 4, and 8). The greatest common factor is the largest common factor shared by the numbers (8).
To find the greatest common factor of 32 and 40, list all of the factors of each.

The greatest common factor is 8.

List the factors of each number below. Then, list the common factors and the greatest common factor.

Question 1.

Explanation:
Factors of 8:                      Factors of 12:
1,2,4,8.                              1,2,3,4,6,12.
Common factors of 8 and 12:
1,2,4.
Greatest common factor of 8 and 12:
4.

Question 2.

Explanation:
Factors of 6:                      Factors of 18:
1,2,3,6.                             1,2,3,6,9,18.
Common factors of 6 and 18:
1,2,3,6.
Greatest common factor of 6 and 18: 6.

Question 3.

Explanation:
Factors of 24:                      Factors of 15:
1,2,3,4,6,8,12,24.                       1,3,5,15.
Common factors of 24 and 15:
1,3.
Greatest common factor of 24 and 15:
3.

Question 4.

Explanation:
Factors of 4:                      Factors of 6:
1,2,4.                                 1,2,3,6.
Common factors of 4 and 6:
1,2.
Greatest common factors of 4 and 6:
2.

Question 5.

Explanation:
Factors of 5:                      Factors of 12:
1,5.                                   1,2,3,4,6,12.
Common factors of 5 and 12:
1.
Greatest common factors of 5 and 12:
1.

Question 6.

Explanation:
Factors of 16:                      Factors of 12:
1,2,4,8,16.                              1,2,3,4,6,12.
Common factors of 16 and 12:
1,2,4.
Greatest common factors of 16 and 12:
4.

Find the greatest common factor for each set of numbers.

Question 1.
a. 7 and 3 _____
Greatest Common factor of 7 and 3: 1.

Explanation:
Factors of 7:                             Factors of 3:
1,7.                                              1,3.

b. 15 and 18 _____
Greatest Common factor of 15 and 18: 3.

Explanation:
Factors of 15:                             Factors of 18:
1,3,5,15.                                       1,2,3,6,18..

Question 2.
a. 14 and 42 ____
Greatest Common factor of 14 and 42: 7.

Explanation:
Factors of 14:                             Factors of 42:
1,7,14.                                              1,2,3,6,7,42.

b. 27 and 18 ____
Greatest Common factor of 27 and 18: 9.

Explanation:
Factors of 27:                             Factors of 18:
1,3,9,27.                                              1,2,3,6,9,18.

Question 3.
a. 36 and 24 ____
Greatest Common factor of 36 and 24: 12.

Explanation:
Factors of 36:                             Factors of 24:
1,2,3,4,6,13,18,9,36.                         1,2,3,6,12,24.

b. 45 and 20 ____
Greatest Common factor of 45 and 20: 5.

Explanation:
Factors of 45:                             Factors of 20:
1,3,5,9,15,45.                                1,2,4,5,10,20.

Question 3.
a. 72 and 54 ____
Greatest Common factor of 72 and 54: 18.

Explanation:
Factors of 72:                             Factors of 54:
1,2,3,4,6,8,9,12,18,36,72.             1,2,3,6,9,18,27,54.

b. 42 and 49 ____
Greatest Common factor of 42 and 49: 7.

Explanation:
Factors of 42:                             Factors of 49:
1,2,3,6,7,14,21,42.                      1,7,49.

Question 4.
a. 72 and 54 ____
Greatest Common factor of 72 and 54: 18.

Explanation:
Factors of 72:                             Factors of 54:
1,2,3,4,6,8,9,12,18,36,72.            1,2,3,6,9,18,27,54

b. 42 and 49 ____
Greatest Common factor of 42 and 49: 7.

Explanation:
Factors of 42:                             Factors of 49:
1,2,3,6,7,14,21,42.                      1,7,49.

Question 5.
a. 86 and 94 ____
Greatest Common factor of 86 and 94: 2.

Explanation:
Factors of 86:                             Factors of 94:
1,2,43,86.                                   1,2,47,94.

b. 66 and 11 ____
Greatest Common factor of 66 and 11: 11.

Explanation:
Factors of 66:                             Factors of 11:
1,2,3,6,22,33,11,66.                         1,11.

Question 6.
a. 52 and 26 ____
Greatest Common factor of 52 and 26: 26.

Explanation:
Factors of 52:                             Factors of 26:
1,2,4,13,26,52.                                1,2,13,26.

b. 12 and 40 ____
Greatest Common factor of 12 and 40: 4.

Explanation:
Factors of 12:                             Factors of 40:
1,2,3,4,6,12.                               1,2,4,10,20,40.

Question 7.
a. 9, 12 and 21 ____
Greatest Common factor of 9, 12 and 21: 3.

Explanation:
Factors of 9:                 Factors of 12:                    Factors of 21:
1,3,9.                             1,2,3,4,6,12.                         1,3,7,21.

b. 16, 32 and 64 ____
Greatest Common factor of 16, 32 and 64: 8.

Explanation:
Factors of 16:                             Factors of 32:                          Factors of 64:
1,2,4,8,16.                                   1,2,4,8,16, 32.                            1,2,4,16,8,32,

Question 8.
a. 15, 25 and 40 ____