Cube Roots Worksheets
Free printable cube roots worksheets: find the cube root of each perfect cube from 8 to 1,000, written with the radical sign. Answer key included.
Each question is a perfect cube under a cube root sign, the radical with a small 3 in its crook: ∛64 = ?. The cube root is the number that, multiplied by itself three times, makes it, so ∛64 is 4, because 4 × 4 × 4 = 64.
The roots run from 2 to 10, so the cubes go from 8 to 1,000. There are only nine of them, so a page of 12 uses every one before any comes back, and no root appears twice in a row. The answer key gives each root as a whole number.
What this worksheet covers
- Find the cube root of a perfect cube
- Relate cube roots to cubing a number
Common Core standards
- 8.EE.A.2 Evaluate square roots of small perfect squares and cube roots of small perfect cubes.
Frequently asked questions
What is a cube root?
The number that multiplies by itself three times to make a given number. 5 × 5 × 5 = 125, so the cube root of 125 is 5, written ∛125 = 5.
What does the small 3 on the radical sign mean?
It is the index, and it says which root to take: a 3 means a cube root. A radical with no index is a square root, so √64 is 8 but ∛64 is 4.
Which numbers are perfect cubes?
The numbers made by cubing a whole number. 1, 8, 27, 64, 125, 216, 343, 512, 729 and 1,000 are the cubes of 1 to 10. Knowing them makes cube roots quick, the way the times tables make division quick.
Can you take the cube root of a negative number?
Yes, unlike a square root: -3 × -3 × -3 = -27, so ∛-27 is -3. These sheets use positive cubes only, which is where eighth grade starts.