# Cube of Numbers

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**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

• 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

8th grade math

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