SHORTCUT TRICK TO FIND CUBE ROOT OF A PERFECT CUBE NUMBER
Here is Shortcut trick to find cube root of a perfect cube number quickly in seconds:
The main point is to memorize the cubes of 1 to 9 and remember their unit’s place number. These will help in solving the cube roots of a number. Here is the table of cubes of number up to 9 for your convenience.
Table of cubes of numbers up to 9.
1 –> 1
2 –> 8
3 –> 27
4 –> 64
5 –> 125
6 –> 216
7 –> 343
8 –> 512
9 –> 729
Since you have remembered the cubes of first 9 natural numbers and their unit digits, now you can easily calculate cube root of numbers quickly and easily.
Below is an example.
Find the cube root of 474552?
STEP 1. Divide the number in 2 parts i.e. 474 (first part) and 552 (second part) starting from right side of given number. (if there are 5 digits in given number, then we will divide it as last 3 numbers as 1st part and starting 2 numbers as part 2)
STEP 2. find the largest cube contained in the first part but that cube should be smaller than the first part (nearest smaller or equal) i.e. 474’s nearest cube which is smaller than 474 is cube of 7=343. Now ten’s part of cube root of 474552 is 7.
STEP 3. Now take part second. See the last digit of the 2nd part and match it with table to see which number’s cube had 2 as the last digit (unit place digit). Since 512 is the number which has 2 in its unit’s place and 512 is cube of 8. Hence 8 is the number which should be at unit’s place.
So our cube root of number 474552 becomes 78.
Let us take another example.
Calculate the cube root of 17576.
Here is the solution to the above problem.
Step 1. Divide in two parts i.e. 17 (1st part- it will determine ten’s place)and 576 (it will determine unit’s place).
Step 2. In first part, the largest cube less than 17 is 8 (which is cube of 2). So, ten’s digit of the cube root of 17576 is 2.
Step 3. In Part 2, the ending digit is 6. Hence, unit’s digit is 6. So, unit’s digit of the cube root of 17576 is 6.
So putting ten’s digit and unit’s digit together, we get 26 as the answer.
You should practice this cube root shortcut trick with just a bit of practice you can easily solve cube root of numbers quickly in seconds.
Now practice by yourself the above given cube root shortcut trick and find the answer to the following questions.
Find the cube root of the following numbers for practice :