Class 8 · Chapter 12

Exponents and Powers

Integer exponents (positive and negative); laws of exponents; scientific notation.

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Detailed theory

a^{-n} = 1/a^n

(

a \ne 0

). E.g.

2^{-3} = 1/8

Key concepts & formulas

a^{-n} = \dfrac{1}{a^n}

(

a\ne 0

a^m \cdot a^n = a^{m+n}

;

\dfrac{a^m}{a^n} = a^{m-n}

;

(a^m)^n = a^{mn}

a^0 = 1

(for

a\ne 0

(ab)^n = a^n b^n

Scientific notation:

k\times 10^n

with

1\le k<10