3/7 : 5/8
2/3 : 4/7
4/5 : 3
1 целая 2/5 : 2/5

$frac{3}{7} : frac{5}{8} = frac{3*8}{7*5} = frac{24}{35}$

$frac{2}{3} : frac{4}{7} = frac{2*7}{3*4} = frac{7}{3*2} = frac{7}{6} = 1frac{1}{6}$

$frac{4}{5} :3= frac{4}{5*3} = frac{4}{15}$

$1 frac{2}{5} : frac{2}{5} = frac{7*5}{5*2} = frac{7}{2}= 3frac{1}{2} =3,5$