# How so you multiply \frac { 3} { 8} \times \frac { 16} { 21}?

Dec 16, 2016

$\frac{2}{7}$

#### Explanation:

When multiplying fractions we look for any $\textcolor{b l u e}{\text{common factors}}$ on the numerators / denominators that we can $\textcolor{b l u e}{\text{cancel}} ,$ that is divide by.

Here 3 and 21 have a common factor of 3 and 8 and 16 have common factors of 2 , 4 and 8. We choose the highest common factor in this case 8.

$\Rightarrow \frac{3}{8} \times \frac{16}{21} = {\cancel{3}}^{1} / {\cancel{8}}^{1} \times {\cancel{16}}^{2} / {\cancel{21}}^{7}$

$= \frac{1 \times 2}{1 \times 7} = \frac{2}{7} \leftarrow \text{ in simplest form}$

A fraction is in $\textcolor{b l u e}{\text{simplest form}}$ when no other factor but 1 will divide into the both the numerator and denominator.