Extra Set

Grade 6 · Unit 1 · L6 · Version A · C441

Greatest common factor and least common multiple

Name ________________

Date ________________

Period ________________

1.
Find the greatest common factor of 45 and 63.
Answer. 9
GCF(45, 63) = 9.
2.
Find the least common multiple of 15 and 17.
Answer. 255
LCM(15, 17) = 2551 = 255.
3.
Find the greatest common factor of 28 and 42.
Answer. 14
GCF(28, 42) = 14.
4.
Find the least common multiple of 14 and 12.
Answer. 84
LCM(14, 12) = 1682 = 84.
5.
Find the greatest common factor of 24 and 72. Then Jonah needs 3 of that amount. What is the total they need?
Answer. 72
GCF(24, 72) = 24. Then multiply by 3: 72.
6.
Find the least common multiple of 11 and 10. Then Nora needs 4 of that amount. What is the total they need?
Answer. 440
LCM(11, 10) = 1101 = 110. Then multiply by 4: 440.
7.
Find the greatest common factor of 27 and 72. Then Priya needs 2 of that amount. What is the total they need?
Answer. 18
GCF(27, 72) = 9. Then multiply by 2: 18.
8.
Find the least common multiple of 5 and 14. Then Owen needs 3 of that amount. What is the total they need?
Answer. 210
LCM(5, 14) = 701 = 70. Then multiply by 3: 210.
9.
Find the greatest common factor of 77 and 66. Then Theo needs 4 of that amount. What is the total they need?
Answer. 44
GCF(77, 66) = 11. Then multiply by 4: 44.
10.
Find the least common multiple of 13 and 14. Then Luis needs 3 of that amount. What is the total they need?
Answer. 546
LCM(13, 14) = 1821 = 182. Then multiply by 3: 546.
11.
Think
Theo tried this problem:
Find the greatest common factor of 35 and 28.
Theo wrote -7. That is not correct. What is the right answer?
Answer. 7
Theo’s answer -7 is off. GCF(35, 28) = 7.
12.
Think
Owen tried this problem:
Find the least common multiple of 16 and 18.
Owen wrote 143. That is not correct. What is the right answer?
Answer. 144
Owen’s answer 143 is off. LCM(16, 18) = 2882 = 144.

Original extra practice. Keys are computed from the items, not guessed.

L6 · Greatest common factor and least common multiple