Practice for GCF and LCM

What are the complete factors of 42?

• 1, 2, 3, 6, 7, 21

• 1, 2, 3, 6, 7, 14, 21, 42

• 1, 2, 6, 7, 21, 42

• 1, 2, 3, 4, 6, 7, 14, 21, 42

What are the first 5 multiples of 6?

• 6, 12, 18, 24, 30

• 2, 4, 6, 8, 12

• 6, 12, 15, 18, 21

• 6, 18, 24, 30, 36

What are the prime factors of 36?

• 2 x 3 x 6

• 2 x 2 x 9

• 2 x 2 x 3 x 3

• 2 x 2 x 2 x 3

What is the greatest common factor of 15 and 25?

• 3

• 5

• 10

• 15

What is the least common multiple of 15 and 25?

• 15

• 25

• 50

• 75

What is the GCF of 12 and 18?

• 24
• 6
• 36
• 3

What is the LCM of 12 and 18?

• 3
• 6
• 36
• 72

14 is the greatest common factor of which two numbers?

• 7 and 14

• 14 and 21

• 28 and 35

• 14 and 42

18 is the least common multiple of what two numbers?

• 6 and 9

• 9 and 12

• 6 and 15

• 3 and 6

In New York City, taxi cabs make a loop around the block every 9 minutes and buses make the loop every 15 minutes.  If they leave a stop at the same time, when will they both be back at the stop again? 

• 3 minutes
• 45 minutes
• 65 minutes
• 30 minutes