Вычислите: (4 6/7:(5/6+8/21)-2 5/13)*8 2/3

Решаем каждый пример:
1) $\frac{5}{6}+ \frac{8}{21}= \frac{5*21}{6*21}+ \frac{8*6}{21*6}= \frac{105}{126}+ \frac{48}{126}= \frac{153}{126}= \frac{17}{14}$

2) $4 \frac{6}{7} : \frac{17}{14}= \frac{4*7+6}{7} : \frac{17}{14}= \frac{34}{7}: \frac{17}{14}= \frac{34}{7}* \frac{14}{17}= \frac{34*14}{7*17}= \frac{4}{1}=4$

3) $4- 2\frac{5}{13}= \frac{4}{1}- \frac{2*13+5}{13}= \frac{4}{1}- \frac{31}{13}= \frac{4*13}{1*13}- \frac{31*1}{13*1}= \frac{52}{13}- \frac{31}{13}= \frac{21}{13}$

4) $\frac{21}{13}*8 \frac{2}{3}= \frac{21}{13}* \frac{8*3+2}{3}= \frac{21}{13} * \frac{26}{3}= \frac{21*26}{13*3}= \frac{14}{1}=14$