# Math help from the Learning Centre

This guide provides useful resources for a wide variety of math topics. It is targeted at students enrolled in a math course or any other Centennial course that requires math knowledge and skills.

## What is an Exponent?

The exponent of a number indicates the number of times the base number is multiplied by itself. For example,

$2^4=2\times 2\times 2\times 2 \qquad \text{or} \qquad \left(\frac{1}{2}\right)^2 = \frac{1}{2} \times \frac{1}{2}$

## Exponent Laws/Rules

 Name How it Works Examples Product Rule When multiplying two numbers with the same base, you can add their exponents together. \begin{align} a^m \times a^n &= a^{m+n} \end{align} \begin{align} 2^2 \times 2^3 &= 2^{2+3} \\ &= 2^5 \\ &= 32 \end{align} \begin{align} 3 \times 3^2 &= 3^{1+2} \\ &= 3^3 \\ &= 27 \end{align} Quotient Rule When dividing two numbers with the same base, you can subtract their exponents. \begin{align} \dfrac{a^m}{a^n} &= a^m \div a^n \\ &= a^{m-n} \end{align} \begin{align} 7^9 \div 7^7 &= 7^{9-7} \\ &= 7^2 \\ &= 49 \end{align} \begin{align} \dfrac{4^{11}}{4^7} &= 4^{11-7} \\ &= 4^4 \\ &= 256 \end{align} Power of a Power Rule Multiply the exponents together. \begin{align} (a^m)^n = a^{mn} \end{align} \begin{align} \left(2^3\right)^4 &= 2^{3\times4} \\ &= 2^{12} \\ &= 4096 \end{align} \begin{align} \left(x^9\right)^2 &= x^{9\times2} \\ &= x^{18} \end{align} Power of a Product Rule Apply the exponent to each factor in the product. For example, \begin {align} (ab)^m = a^mb^m \end{align} or \begin{align} (abc)^m = a^mb^mc^m \end{align} (no matter how many factors there are, the rule still applies in the exact same way.) \begin{align} \left(2^2g^3\right)^3 &= \left(2^2\right)^3\left(g^3\right)^3 \\ &= 2^6g^9 \\ &= 64g^9 \end{align} \begin{align} \left(3x^2y^4\right)^2 &= \left(3^2\right)\left(x^2\right)^2\left(y^4\right)^2 \\ &= 9x^4y^8 \end{align} \begin{align} \left(5xyz^2\right)^3 &= 5^3x^3y^3\left(z^2\right)^3 \\ &= 125x^3y^3z^6 \end{align} Power of a Quotient Rule Apply the exponent to the numerator and denominator separately. \begin{align} \left(\frac{a}{b}\right)^m &= \dfrac{a^m}{b^m} \end{align} \begin{align} \left(\frac{2}{3}\right)^2 &= \dfrac{2^2}{3^2} \\ &= \dfrac{4}{9} \end{align} \begin{align} \left(\frac{4x^2}{3y}\right)^4 &= \dfrac{\left(4x^2\right)^4}{\left(3y\right)^4} \\ &= \dfrac{\left(4^4\right)\left(x^2\right)^4}{\left(3^4\right)\left(y^4\right)} \\ &= \dfrac{256x^8}{81y^4} \end{align}

## Special Exponents

Negative Exponents

A negative exponent signals a reciprocal of the base and exponents. Once the reciprocal is performed, the negative exponent becomes positive.

$2^{-3}=\frac{1}{2^3}=\frac{1}{8}$

This can also be interpreted as moving a value from the top of the fraction to the bottom and vice versa.

$\frac{1}{4^{-3}}=\frac{4^3}{1}=64\qquad \frac{3^{-5}}{2^{-2}} = \frac{2^{2}}{3^{5}} = \frac{4}{243}$

Power of 1

Any base to the exponent of 1 equals itself.

$13^1=13 \qquad \pi^1=\pi \qquad (2.2)^1=2.2$

Power of 0

Any non-zero number with the exponent 0 equals to 1.

$5^0=1 \qquad x^0=1 \qquad \left(\frac{17}{19}\right)^0=1 \qquad \left(-4\right)^0 = 1$