Find the cube root of any number — the value that, when multiplied by itself three times, gives your number. Unlike square roots, negative numbers do have real cube roots.
The cube root is the number that gives your input when multiplied by itself three times.
A negative input gives a negative cube root, because a negative multiplied three times stays negative.
If the result is a whole number, the input is a perfect cube.
Cube root: ∛n = x where x × x × x = n
Also written: n^(1/3)
Finding the cube root of −27.
Number: −27
Look for a number that cubed gives −27
(−3) × (−3) = 9, then 9 × (−3) = −27
−27 is so a perfect cube
Answer: ∛−27 = −3
Why do negative numbers have cube roots but not square roots?
Cubing keeps the sign the same — multiplying three negative numbers together still gives a negative result. Squaring always gives a positive result, so no real number squares to a negative one.
What is a perfect cube?
A number whose cube root is a whole number — like 1, 8, 27, 64, 125, and so on.