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Grade 8 Math — Cubes and cube roots

Cube a number, recognize a perfect cube, and find a cube root by prime factorisation.

Name: ________________________

  1. 1.The prime factors of 5832 are 2 × 2 × 2 × 3 × 3 × 3 × 3 × 3 × 3. What is the cube root of 5832?

  2. 2.Put these in order by value, smallest first.

    • The cube of 3
    • The cube root of 8000
    • The cube root of 8
    • The cube root of 64
    • The cube of 2

  3. 3.What happens when a negative number is cubed?

    • a) It becomes zero
    • b) It stays negative
    • c) A negative number cannot be cubed
    • d) It turns positive

  4. 4.Match each number to its cube.

    • 2
    • 3
    • 5
    • 9
    • 11
    • 125
    • 27
    • 1331
    • 729
    • 8

  5. 5.What is 7 cubed?

  6. 6.What is the cube root of -125?

  7. 7.Which of these is a perfect cube?

    • a) 500
    • b) 512
    • c) 1200
    • d) 600

  8. 8.What is the cube root of 1000?

Answer key — Grade 8 Math — Cubes and cube roots

  1. 1. 18
  2. 2. 1. The cube root of 8 2. The cube root of 64 3. The cube of 2 4. The cube root of 8000 5. The cube of 3
  3. 3. b) It stays negative
  4. 4. 2 → 8; 3 → 27; 5 → 125; 9 → 729; 11 → 1331
  5. 5. 343
  6. 6. -5
  7. 7. b) 512
  8. 8. 10