Fraction and Indices

Numbers II

Fraction and Indices

memorize (calculation of fraction)

 $\frac{m}{k}+\frac{m}{l}\ne\frac{m}{k+l}$  

 $\frac{a}{b}+\frac{c}{b}=\frac{a+c}{b}$  

 $\frac{a}{b}+\frac{c}{d}=\frac{\left(a\times d\right)+\left(c\times b\right)}{b\times d}$  

example

1. $\frac{3}{4}\times\frac{5}{6}=\frac{\left(3\times6\right)+\left(4\times5\right)}{4\times6}$  

 $\frac{18+20}{24}=\frac{38}{24}=\frac{19}{12}=1\ \frac{7}{12}$  

2.  $\frac{5}{6}-\frac{1}{2}=\frac{\left(5\times2\right)-\left(6\times1\right)}{6\times2}\ =\ \frac{10-6}{12}=\frac{4}{12}=\frac{1}{3}$  

memorize Orders/Indices/Exponent

 $a^m\times a^n=\ a^{m+n}$  
 $a^m\div a^n=a^{m-a}$  
 $a^m+2a^m=\ 3a^m$