Вычислите 1 5/15+2 1/15 3 7/12-1 3/12 1 11/15+2 8/15 3 7/12-2 11/12

Задание: Вычислите
$1\frac{5}{15} + 2\frac{1}{15} = (1+2) + ( \frac{5}{15} + \frac{1}{15}) = 3\frac{6}{15} = 3\frac{2}{5}$

$3\frac{7}{12} - 1\frac{3}{12} = (3-1) + (\frac{7}{12} - \frac{3}{12} ) = 2\frac{4}{12} = 2\frac{1}{3}$

$1\frac{11}{15} + 2\frac{8}{15} = (1+2) + ( \frac{11}{15} + \frac{8}{15}) = 3 \frac{19}{15} = 4\frac{4}{15}$

$3\frac{7}{12} - 2\frac{11}{12} = 2 \frac{19}{12} - 2\frac{11}{19} = \frac{8}{12} = \frac{2}{3}$