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How to Find the Cube Root of a Number in a Calculator?

Published in Calculator Use 3 mins read

Most modern calculators have a dedicated cube root function. Here's how to find the cube root of a number:

1. Check for a Dedicated Cube Root Button:

  • Look for a button that looks like this: ∛x or x^(1/3) or y^(1/x)
  • Some calculators may require you to press a "shift" or "2nd" key to access this function. The cube root function might be located above another key (often the square root key).

2. Using the Dedicated Cube Root Button:

  • Input the number: Type the number for which you want to find the cube root.
  • Press the cube root button: Press the ∛x or x^(1/3) button (or shift + the relevant key).
  • View the result: The calculator will display the cube root of the number.

Example: To find the cube root of 27:

  1. Enter 27 into the calculator.
  2. Press the ∛x button.
  3. The display should show 3.

3. Using the Power Function (If No Cube Root Button):

If your calculator doesn't have a dedicated cube root button, you can use the power function. The cube root of a number is the same as raising that number to the power of 1/3 (or approximately 0.333333333).

  • Input the number: Type the number.
  • Press the power button: Look for a button that looks like this: ^ or x^y or y^x
  • Enter the exponent: Type (1/3) or 0.333333333. Make sure to use parentheses around 1/3.
  • Press the equals button: Press the = button.
  • View the result: The calculator will display the cube root of the number.

Example: To find the cube root of 27:

  1. Enter 27 into the calculator.
  2. Press the ^ button.
  3. Enter (1/3) or 0.333333333.
  4. Press the = button.
  5. The display should show 3.

Approximate Method (For Calculators Without Exponent or Cube Root):

This method from the provided reference is less precise, but works on very basic calculators:

  1. Write the number on your calculator.
  2. Press the square root button 12 times.
  3. Subtract 1.
  4. Divide by 3 (for cube root. For other roots, divide by the corresponding root value).
  5. Add 1.
  6. Press "multiply button and then equal to button" 12 times (i.e. multiply equal to multiply equal to..... 12 times).

Example (Cube Root of 8):

  1. Enter 8
  2. Press the square root button 12 times.
  3. Subtract 1.
  4. Divide by 3.
  5. Add 1.
  6. Press x then = button 12 times. You should see a result close to 2 (the cube root of 8).

This method leverages the properties of repeated square roots and is an approximation. It's generally better to use a dedicated cube root button or the power function if available.

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