Greatest common factor, least common multiple

Answer Key - Grade 6 Math Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   Esme races the clock on a number puzzle. What is the greatest common factor of 28 and 42?

   14
2. 2.

   Jun solves a number puzzle. What is the greatest common factor of 30 and 45?

   15
3. 3.

   Noah follows a map clue. What is the least common multiple of 4 and 9?

   36
4. 4.

   Tala finds a hint in a book. What is the least common multiple of 4 and 12?

   12
5. 5.

   Ari coaches kickball and has 32 red play balls and 40 yellow play balls. Ari sets up identical drill areas with none left over. What is the greatest number of areas?

   8
6. 6.

   Jun's robot has a red light that blinks every 9 seconds and a green light every 12 seconds. They blink together now. In how many seconds do they next blink together?

   36
7. 7.

   Kira waters the plants every 4 days and cleans the fish tank every 7 days. Kira does both today. In how many days will Kira next do both on the same day?

   28
8. 8.

   Luz rewrites a sum. Write 36 + 8 as the greatest common factor times a sum. What number goes in front of the parentheses?

   4
9. 9.

   Milo rewrites a sum. Write 24 + 40 as the greatest common factor times a sum. What number goes in front of the parentheses?

   8
10. 10.

    Ren picks a card. Which expression is 42 + 28 with the greatest common factor taken out?

    • 14(3 + 28)
    • 2(21 + 14)
    • 14(3 + 2)
    • 6(7 + 28)