## Elementary Technical Mathematics

$3\displaystyle \frac{1}{4}$
$\displaystyle \left(\frac{-6}{8} \right)-\left(-4 \right) = \qquad$ Change the sign of the number being subtracted and add. Also reduce $\displaystyle \frac{-6}{8}$ to lowest terms. $=\displaystyle \left(\frac{-3}{4} \right)+\left(+4 \right)$ We can write 4 as $3+1=3+\displaystyle \frac{4}{4}=3\frac{4}{4}$ $=\displaystyle \left(\frac{-3}{4} \right)+\left(+3\frac{4}{4} \right)$ Add as mixed numbers: $=3+\displaystyle \frac{-3+4}{4}$ Apply rule: adding two numbers with unlike signs $=3\displaystyle \frac{1}{4}$