# How do you use the distributive property to rewrite and evaluate 5*89?

Sep 18, 2016

Write 89 as an addition or subtraction using a multiple of 10.

$445$

#### Explanation:

This is SUCH a nifty technique and one you can use in mental calculations to make things quicker and easier -and probably more accurate too.

No-one knows the 89 times table! Rewrite 89 in a different form.

$5 \times \textcolor{red}{89}$

= $5 \times \textcolor{red}{\left(90 - 1\right)} \text{ } \leftarrow$ use the distributive law

=$450 - 5$

= $445$

OR

$5 \times \textcolor{red}{89}$

= $5 \times \textcolor{red}{\left(80 + 9\right)} \text{ } \leftarrow$ use the distributive law

=$400 + 45$

=$445$