Answer:

Least common multiply (LCM)

A. 20

B. 24

C. 60

Solution:

A. 4 and 10Multiples of 4: 4, 8, 12, 16, 20, 24, 28Multiples of 10: 10, 20, 30, 40

Therefore,

LCM(4, 10) = 20

B. 6 and 8Multiples of 6: 6, 12, 18, 24, 30, 36Multiples of 8: 8, 16, 24 , 32, 40

Therefore,

LCM(6, 8) = 24

C. 6, 10 and 12Multiples of 6: 6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72Multiples of 10: 10, 20, 30, 40, 50, 60, 70, 80Multiples of 12: 12, 24, 36, 48, 60, 72, 84

Therefore,

LCM(6, 10, 12) = 60

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Greatest common factor (GCF)

D. 4

E. 1

Solution:

D. 4 and 20The factors of 4 are: 1, 2, 4The factors of 20 are: 1, 2, 4, 5, 10, 20

Then the greatest common factor is 4.

E. 7 and 9The factors of 7 are: 1, 7The factors of 9 are: 1, 3, 9

Then the greatest common factor is 1.