Evaluate $2v$2v when $v=-3$v=−3.

Find the value of $\frac{r}{5}$r5 when $r=-20$r=−20.

Evaluate $\frac{5c}{2}$5c2 when $c=-4$c=−4.

Evaluate $\frac{15}{r}$15r when $r=-3$r=−3.

Generalise the properties of operations with fractional numbers and integers.