Powers and Roots

Number • Topic 4 • intermediate

🔢 Powers and Indices

A power (or index) tells us how many times to multiply a number by itself.

Understanding Powers

= 2 × 2 × 2 = 8

= 5 × 5 = 25

= 4

3⁰ = 1 (any number⁰ = 1)

Laws of Indices

aᵐ × aⁿ = aᵐ⁺ⁿ

aᵐ ÷ aⁿ = aᵐ⁻ⁿ

(aᵐ)ⁿ = aᵐˣⁿ

a⁻ⁿ = 1/aⁿ

√ Square and Cube Roots

Roots are the opposite of powers. They ask "what number, when raised to this power, gives us this result?"

Square Root

√16 = 4

Because 4² = 16

Cube Root

∛27 = 3

Because 3³ = 27

Perfect Squares

1, 4, 9, 16, 25, 36, 49, 64, 81, 100...

🔬 Standard Form

Standard form (scientific notation) is a way to write very large or very small numbers more easily.

Format: a × 10ⁿ

Where: 1 ≤ a < 10 and n is an integer

Large Numbers:

45,000 = 4.5 × 10⁴

7,200,000 = 7.2 × 10⁶

Small Numbers:

0.0034 = 3.4 × 10⁻³

0.000056 = 5.6 × 10⁻⁵

🎯 Interactive Practice

1. Calculate: 2⁴

2. Express 340,000 in standard form