$\frac{5}{10}=\frac{5:5}{10 : 5}=\frac{1}{2}$

$\frac{3}{15}=\frac{3:3}{15: 3}=\frac{1}{5}$

$\frac{40}{70}=\frac{40:10}{70 : 10}=\frac{4}{7}$

$\frac{24}{36}=\frac{24:12}{36: 12}=\frac{2}{3}$

$\frac{70}{42}=\frac{70:14}{42: 14}=\frac{5}{3}$