Cubing made easy
Cube of a number is that the number multiplied by itself thrice.
We shall discuss some simple methods to calculate the cube problems easily and perfectly.
There few to properties to remember…
Perfect cube
The first 20 perfect cubes are as follows,
Cubing Numbers
The cube of any number can be found by using the following two formulas:
(x+y)3 = x3 + 3x2 y + 3xy2 + y3
(x-y)3 = x3 – 3x2 y + 3xy2 – y3
Using this formulae, we can solve the following problems.
Find the cube of 211.
(200+11)3 = 2003 + 3 (200)2 11 + 3(200)(11)2 + 113
= 8000000 + 3 (40000) 11 + 600(121) + 1331
= 8000000 + 1320000 + 72600 +1331 = 9393931.
Find the cube of 199.
(200-1)3 = 2003 – 3 (200)2 1 + 3(200)(1)2 – 13
= 8000000 – 3 (40000) 1 + 600(1) – 1
= 8000000 – 120000 + 600 – 1 = 7880599.
