ANY TWO DIGIT NUMBER
With this method we can find cube of any two digit number.
We have to write the numbers in four places
- Write cube of first digit of the given number in the first place and cube of second digit of the given number in the last(4th) place
- Take square of first digit and multiply by the second digit and keep the result in the 2nd place
- Then take square of second digit and multiply by the first digit and keep the result in the 3rd place
- Double the 2nd and 3rd place numbers and add to 2nd and 3rd place numbers respectively
- Now add all the numbers to get the cube of the given number Let us take an example and understand this method.
- We find cube of 26
⇒ First write cube of 2 in the first place and cube of 6 in the last place
8 ( ) ( ) 216 - ⇒ Take square of 2 and multiply by 6 and keep the result in the 2nd place 2 2 × 6 = 24
8 24 ( ) 216 - ⇒ Take square of 6 and multiply by 2 and keep the result in the 3rd place 6 2 × 2 = 72
8 24 72 216 - ⇒ Now double the middle numbers and add
8 24 72 216
48 144
(9) (23) (21) ← Carry
17 5 7 6
∴ 263 = 17576