Prime factors and perfect squares

Answer Key - Grade 6 Math Worksheet - Building Confidence

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

1. 1.

   Esme is stuck on a riddle: only one of these numbers is prime. Which one is it?

   • 21
   • 10
   • 1
   • 13
2. 2.

   Milo builds a factor tree for 20. You can type 5 × 5 × 7 or 5^2 × 7. What is 20 as a product of primes?

   2, 2, 5
3. 3.

   Noah picks a card. Which one shows 28 as a product of primes?

   • 1 × 2 × 2 × 7
   • 2 × 2 × 7
   • 4 × 7
   • 2 × 7
4. 4.

   Tala picks a card. Which one shows 30 as a product of primes?

   • 1 × 2 × 3 × 5
   • 2 × 3 × 5
   • 5 × 6
5. 5.

   Zee draws a factor tree for 42. It splits first into 2 and 21. Then 21 splits into 3 and 7. What is the missing prime?

6. 6.

   Bo draws a factor tree for 70. It splits first into 5 and 14. Then 14 splits into 2 and 7. What is the missing prime?

7. 7.

   Esme starts a factor tree for 36 with 36 = 4 × 9. After finishing the tree, what is 36 as a product of primes?

   2, 2, 3, 3
8. 8.

   Milo reads 3² in a puzzle. What is 3²?

   9
9. 9.

   Noah reads 4² in a puzzle. What is 4²?

   16
10. 10.

    Pia reads 5² in a puzzle. What is 5²?

    25