$latex\frac{3}{7} \add \frac{1}{3} \div \frac{-1}{7} $ – $latex \frac{-1}{9}$
$latex\frac{16}{21} \div \frac{-9}{63} $ – $latex \frac{-7}{63}$
$latex\frac{16}{21} \div \frac{-16}{63}$
$latex\frac {-9}{3}=$
$latex{-3}$
Yelllow = positive
blue = negative
