Решите плиз,срочно надо,оч быстро

Решите задачу:

$( \frac{7}{12} + \frac{4}{15} ) \div \frac{51}{60 } \times \frac{27}{34} = \frac{27}{34}$

$1) \frac{7}{12} + \frac{4}{15} = \frac{35}{60} + \frac{16}{60} = \frac{51}{60} \\ = \frac{17}{20}$

$1) \frac{7}{12} + \frac{4}{15} = \frac{35}{60} + \frac{16}{60} = \frac{51}{60} \\2) \frac{51}{60} \div \frac{51}{60} = \frac{51}{60} \times \frac{60}{51} = 1$

$3)1 \times \frac{27}{34} = \frac{27}{34}$

$( \frac{2}{5} - \frac{1}{6} ) \div \frac{49}{60} = \frac{2}{7}$

$1) \frac{2}{5} - \frac{1}{6} = \frac{12}{30} - \frac{5}{30} = \frac{7}{30} \\ 2) \frac{7}{30} \div \frac{49}{60} = \frac{7}{30} \times \frac{60}{49} = \frac{2}{7}$