Find Cube Root of Any Number in 5 Seconds - Mathematics Shortcuts and Tricks

Here is mathematical trick to find cube root of any number without the help of pen/ pencil in few seconds. Shortcut tricks are very helpful for fast calculations in competitive exams as time allotted is too less for lengthy calculations. So shortcut tricks helps us to solve questions in very less time hence improving chances of getting good score and higher rank in merit.

Find Cube Root of Any Number

Instructions:

• Number must be a perfect cube.
• You must know cubes of number from 1 to 9.

(1)³ = 1;     (2)³ = 8;     (3)³ = 27;     (4)³ = 64     (5)³ = 125     (6)³ = 216     (7)³ = 343     (8)³ = 512;     (9)³ = 729;

Hence we know:

• If last digit of a number is 1, last digit of its cube must be 1
• If last digit of a number is 2, last digit of its cube must be 8
• If last digit of a number is 3, last digit of its cube must be 7
• If last digit of a number is 4, last digit of its cube must be 4
• If last digit of a number is 5, last digit of its cube must be 5
• If last digit of a number is 6, last digit of its cube must be 6
• If last digit of a number is 7, last digit of its cube must be 3
• If last digit of a number is 8, last digit of its cube must be 2
• If last digit of a number is 9, last digit of its cube must be 9
• If last digit of a number is 0, last digit of its cube must be 0

To find cube root of any number follow steps below:

1. First find unit digit of cube root from last digit of number. ( If last digit of number is 2, last digit of the cube root must be 8 or if last digit of number is 4, last digit of the cube root must be 4)
2. Now ignore last 3 digits of the number and find lowest nearest cube root of the number. ( if number is 12167 we will ignore 167 and lowest nearest cube root of 12 is 2 ((2)³ = 8)
3. Append last digit to this number and this is your answer.

Follow examples below to understand it better:

Eg. 1: 

Find cube root of 19683
Step -1 => Here last digit is 3, so corresponding cube root's last digit must be 7.
Step -2 => Now we will ignore 683 (last three digits) and number we are left with is 19.
Step -3 => Perfect lowest cube near 19 is 8 and its cube root is 2.
Step -4 => Appending unit's digit with 2 we got 27.

Hence cube root of 19683 is = 27. (Ans)

Eg. 2: 

Find cube root of 79507
Step -1 => Here last digit is 7, so corresponding cube root's last digit must be 3.
Step -2 => Now we will ignore 507 (last three digits) and number we are left with is 79.
Step -3 => Perfect lowest cube near 79 is 64 and its cube root is 4.
Step -4 => Appending unit's digit with 4 we got 43.

Hence cube root of 79507 is = 43. (Ans)

To understand it better watch this video

 

Try cube root of these numbers:

• 2197 =
• 5832 = 
• 17576 = 
• 85184 =
• 328509 = 

Mathematics is all about practice. Practice more and more problems of this type to improve your speed.

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