Cube of Numbers

Cube of Numbers : The number with exponent 3 is called cube.
The word ‘cube’ is used in geometry. A cube is a solid figure which has all its sides equal.
There are only ten perfect cubes from 1 to 1000.
If a number is a number, then the cube of a is a
3 ,
a x a x a = a
3

Examples
1. 2
3 = 2 x 2 x 2 = 8, that is the cube of 2 is 8.

2. 3
3 = 3 x 3 x 3 = 27, that is the cube of 3 is 27.

3. 4
3 = 4 x 4 x 4 = 64, that is the cube of 4 is 64.

4. (1.2)
3 = 1.2 x 1.2 x 1.2 = 1.728

5. (2/3)
3 = 2/3 x 2/3 x 2/3 = 8/27

A natural number is said to be a perfect cube if it is the cube of some natural number.

Example
8 = 2 x 2 x 2
8 = 2
3
8 is the perfect cube because it is a cube of 2 which is a natural number.
But 12 is not a perfect cube because it is not a cube of any natural numbers.

Practice


Q.1 Find the cube of :
1) 6
3
2) (-7)
3
3) b
3
4) (1/8)
3
5) (0.5)
3

Q.2 Which of the following numbers are perfect cube.
1) 125
2) 15
3) 27
4) 36
5) 343
6) m
3
7) 1/8
8) 27/216
9) -1/64
10) 49/729

Cube and Cube Roots

Cube of Numbers
Perfect-Cube
Properties - Cube
Cube by Column method
Negative numbers-cube
Cube - Rational numbers
Cube-Root
Finding cube root by Prime Factorization
Cube root of Rational numbers
Estimating cube-root

From Cube - numbers to Exponents

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