Найдите значение выражения. 4целых-(41/84-5/21)+7целых11/30

Решите задачу:

$4-( \frac{41}{84} - \frac{5}{21} )+ 7 \frac{11}{30} = 4-( \frac{41}{84} - \frac{20}{84} )+ 7 \frac{11}{30} = \\ 4- \frac{41-20}{84} + 7 \frac{11}{30} = 4- \frac{21}{84} + 7 \frac{11}{30} = \\ = 4- \frac{1}{4} + 7 \frac{11}{30} =3 \frac{3}{4} + 7 \frac{11}{30} = \\ \frac{3*4+3}{4} + \frac{7*30+11}{30} = \frac{15}{4} + \frac{221}{30} = \\ \frac{15*15}{60} + \frac{221*2}{30}= \frac{225}{60} + \frac{442}{30}= \\ \frac{225+442}{60} = \frac{667}{60} = 11 \frac{7}{60}$