Найдите значения выражения: (21/22-5/11)-(22/39-3/13)

Решите задачу:

$(\frac{21}{22}-\frac{5}{11}) - (\frac{22}{39}-\frac{3}{13}) = (\frac{21}{22}-\frac{5*2}{11*2}) - (\frac{22}{39}-\frac{3*3}{13*3}) = = (\frac{21}{22}-\frac{10}{22}) - (\frac{22}{39}-\frac{9}{39}) = \frac{21-10}{22}-\frac{22-9}{39}=\frac{11}{22}-\frac{13}{39}=\frac{1}{2}-\frac{1}{3}=\frac{1*3-1*2}{6}=\frac{1}{6}$