4целых-3\5=? 15целых-6\7=? 3целых1\5-1целая3\5=? 2целых4\9-1целая7\9=?

$4-\frac{3}{5}=\frac{20-3}{5}=\frac{17}{5}=3\frac{2}{5}$

$15-\frac{6}{7}=\frac{105-6}{7}=\frac{99}{7}=14\frac{1}{7}$

$3\frac{1}{5}-1\frac{3}{5}=\frac{16}{5}-\frac{8}{5}=\frac{16-8}{5}=\frac{8}{5}=1\frac{3}{5}$

$2\frac{4}{9}-1\frac{7}{9}=\frac{22}{9}-\frac{16}{9}=\frac{22-16}{9}=\frac{6}{9}=\frac{2}{3}$