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.

   Bo picks a card. Which number is the prime number?

   • 15
   • 1
   • 14
   • 11
2. 2.

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

   • 13
   • 21
   • 1
   • 10
3. 3.

   Jun finds a riddle in a book. Which number has just two factors, itself and one?

   • 1
   • 27
   • 17
   • 16
4. 4.

   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
5. 5.

   Ren picks a card. Which one shows 50 as a product of primes?

   • 2 × 5 × 5
   • 2 × 25
   • 2 × 5
   • 1 × 2 × 5 × 5
6. 6.

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

   • 5 × 6
   • 2 × 3 × 5
   • 1 × 2 × 3 × 5
7. 7.

   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?

8. 8.

   Jun starts a factor tree for 27 with 27 = 3 × 9. After finishing the tree, what is 27 as a product of primes?

   3, 3, 3
9. 9.

   Luz starts a factor tree for 32 with 32 = 4 × 8. After finishing the tree, what is 32 as a product of primes?

   2, 2, 2, 2, 2
10. 10.

    Zee is stuck on a riddle: only one of these numbers is a perfect square. Which one is it?

    • 35
    • 38
    • 42
    • 36