# How do you solve and check your solutions to 1/2m=21?

Sep 27, 2016

$m = 42$

#### Explanation:

"Half of something is 21"..... the whole something is 42

Do the maths..

$\textcolor{red}{2 \times} \frac{1}{2} m = \textcolor{red}{2 \times} 21 \text{ } \leftarrow \times 2$ on both sides to cancel

$m = 42$

TO check: substitute 42 in the place of m.

$\frac{1}{2} \left(42\right)$

=$21$

This is the same as the answer that was given, so we have the correct value for m.