Question

Using suitable rearrangement and find the sum,
$\frac{4}{7}+\left(\frac{-4}{9}\right)+\frac{3}{7}+\left(\frac{-13}{9}\right)$

Answer 1

$\frac{4}{7}+(\frac{-4}{9})+\frac{3}{7}+(\frac{-13}{9})=\frac{4+3}{7}-\frac{13+4}{9}=1-\frac{17}{9}=\frac{9-17}{9}=\frac{-8}{9}$