1/2+5/7; 4/5+1/6; 1/2-1/3; 1/3-1/4; 2/3-1/5; 5/7-2/3: решите пожалуста

Решите задачу:

$\frac{1}{2}+\frac{5}{7} =\frac{7+10}{14}= \frac{17}{14} = 1 \frac{3}{14};$
$\frac{4}{5} + \frac{1}{6} = \frac{24+5}{30} =\frac{29}{30};$
$\frac{1}{2} - \frac{1}{3} = \frac{3-2}{6} = \frac{1}{6} ;$
$\frac{1}{3} - \frac{1}{4}= \frac{4-3}{12}= \frac{1}{12} ;$
$\frac{2}{3} - \frac{1}{5} = \frac{10-3}{15} = \frac{7}{15};$
$\frac{5}{7} - \frac{2}{3}= \frac{15-14}{21}= \frac{1}{21} ;$