Решите пример 4-(4 21/40 - 5,25): 1 7/20 Го))

Решите задачу:

$4-(4 \frac{21}{40}-5,25):1 \frac{7}{20} \\ \\ 4 \frac{21}{40}-\frac{525}{100}=\frac{181}{40}-\frac{21}{4}=\frac{181-10*21}{40}=-\frac{29}{40} \\ \\ -\frac{29}{40}:1 \frac{7}{20}=-\frac{29}{40}:\frac{27}{20}=-\frac{29}{40}*\frac{20}{27}=-\frac{29}{54} \\ \\ 4+\frac{29}{54}=\frac{54*4+29}{54}=\frac{245}{54}=4\frac{29}{54}$