# What is 10/21 -: 18/7?

Jun 18, 2018

See a solution process below:

#### Explanation:

We can rewrite the expression as:

$\frac{\frac{10}{21}}{\frac{18}{7}}$

Now, use this rule for dividing fractions:

$\frac{\frac{\textcolor{red}{a}}{\textcolor{b l u e}{b}}}{\frac{\textcolor{g r e e n}{c}}{\textcolor{p u r p \le}{d}}} = \frac{\textcolor{red}{a} \times \textcolor{p u r p \le}{d}}{\textcolor{b l u e}{b} \times \textcolor{g r e e n}{c}}$

$\frac{\frac{\textcolor{red}{10}}{\textcolor{b l u e}{21}}}{\frac{\textcolor{g r e e n}{18}}{\textcolor{p u r p \le}{7}}} \implies \frac{\textcolor{red}{10} \times \textcolor{p u r p \le}{7}}{\textcolor{b l u e}{21} \times \textcolor{g r e e n}{18}} \implies \frac{\textcolor{red}{2 \times 5} \times \textcolor{p u r p \le}{7 \times 1}}{\textcolor{b l u e}{7 \times 3} \times \textcolor{g r e e n}{2 \times 9}} \implies \frac{\textcolor{red}{\textcolor{b l a c k}{\cancel{\textcolor{red}{2}}} \times 5} \times \textcolor{p u r p \le}{\cancel{\textcolor{b l a c k}{\textcolor{p u r p \le}{7}}} \times 1}}{\textcolor{b l u e}{\textcolor{b l a c k}{\cancel{\textcolor{b l u e}{7}}} \times 3} \times \textcolor{g r e e n}{\textcolor{b l a c k}{\cancel{\textcolor{g r e e n}{2}}} \times 9}} \implies \frac{\textcolor{red}{5} \times \textcolor{p u r p \le}{1}}{\textcolor{b l u e}{3} \times \textcolor{g r e e n}{9}} \implies \frac{5}{27}$