Grade 8 Squares, Cubes & Roots worksheet
from Gradelings · Name: ______________________
How to explain it
- A square number is a number times itself: 3² = 3 × 3 = 9.
- A square root undoes a square: √81 = 9.
- A cube is a number multiplied 3 times: 2³ = 2 × 2 × 2 = 8.
Example: What is √81 + 3²? √81 = 9, because 9 × 9 = 81. 3² = 9. 9 + 9 = 18. Answer: 18
Question 1
What is 5²?
answer box
25
Hint: 5² means 5 × 5 = 25.
Question 2
What is √81?
answer box
9
Hint: Which number multiplied by itself makes 81? 9 × 9 = 81, so √81 = 9.
Question 3
Which of these numbers is a perfect square?
- 80
- 82
- 83
- 81
81
Hint: A perfect square is a whole number times itself. 9 × 9 = 81.
Question 4
√156 is between which two whole numbers?
- 13 and 14
- 10 and 11
- 12 and 13
- 11 and 12
12 and 13
Hint: 12² = 144 and 13² = 169. Since 156 is between them, √156 is between 12 and 13.
Question 5
A square floor tile has sides of 7 cm. What is its area?
answer boxcm²
49 cm²
Hint: Area of a square = side × side = 7 × 7 = 49 cm².
Question 6
√48 is closest to which whole number?
- 5
- 7
- 8
- 6
7
Hint: 6² = 36 and 49 = 7². 48 is closer to 49, so √48 is closest to 7.
Question 7
Which is greater, √87 or 9?
- They are equal
- 9
- √87
√87
Hint: 9² = 81, and 87 is more than 81. So √87 is a little more than 9.
Question 8
What is 8³?
answer box
512
Hint: 8³ means 8 × 8 × 8 = 64 × 8 = 512.
Question 9
Which of these numbers is a perfect cube?
- 72
- 511
- 513
- 512
512
Hint: A perfect cube is a whole number multiplied by itself three times. 8 × 8 × 8 = 512.
Question 10
What is 12²?
answer box
144
Hint: 12² means 12 × 12 = 144.
Answer key
- 1. 25
- 2. 9
- 3. 81
- 4. 12 and 13
- 5. 49 cm²
- 6. 7
- 7. √87
- 8. 512
- 9. 512
- 10. 144
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