How to Calculate Cube Root of a Number in 10 Seconds

[dineshhx]

The first and the most important step is to memorize the cubes of 1 to 9. These would form an important part of your toolkit in solving the cube roots. Here is a table for your convenience.

1 –> 1
2 –> 8
3 –> 27
4 –> 64
5 –> 125
6 –> 216
7 –> 343
8 –> 512
9 –> 729

Once you memorize this list, the next step is to remember the last digit (unit digit) of each of these cubes. Here is the list again, only with unit digits this time.

1 –> 1
2 –> 8
3 –> 7
4 –> 4
5 –> 5
6 –> 6
7 –> 3
8 –> 2
9 –> 9

That’s it. Now that you have memorized the cubes of first 9 natural numbers and their unit digits, you are all set to amaze your friends by calculating cube roots within 5 seconds (given that they have not read this article).

Calculate the cube root of 941192.
Step 1 —– We get two parts i.e. 941 and 192.
Step 2 —– The largest cube less than 941 is 729 (cube of 9). So, ten’s digit is 9.
Step 3 —– The ending digit is 2. Hence, unit’s digit is 8. That’s it. 98 is the answer.
Practice it a bit and you would be able to solve this in even less than 5 seconds.

You can verify your answer using a calculator.

 

[MarkFL]

Neat trick! (Yes)

I have moved the thread here since it is not about getting the solution to a problem, and I have removed the link to the online calculator...we have a widget here that will do such calculations, and our users also all have their favorite online calculators or dedicated graphing calculators anyway, so there is no need for such a link. :D