Найдите значение выражения (3/4-4/5)×7,8-(2/3+4/7)×(-7/13) пжл

( $\frac{3}{4} - \frac{4}{5})*7,8-(\frac{2}{3}+\frac{4}{7})*(\frac{-7}{13}) = \frac{83}{300}$

1) $\frac{3}{4} - \frac{4}{5} = \frac{15}{20} - \frac{16}{20} = \frac{-1}{20}$

НОЗ: 20.

2) $\frac{2}{3} + \frac{4}{7} = \frac{14}{21} + \frac{12}{21} = \frac{26}{21}$

НОЗ: 21.

3) $\frac{26}{21} * -\frac{7}{13}$ = $-\frac{2}{3}$

4) $\frac{-1}{20} * 7\frac{8}{10} = -\frac{1}{20} * \frac{78}{10} = -\frac{39}{100}$

5) $-\frac{39}{100} + \frac{2}{3} = -\frac{117}{300} + \frac{200}{300} = \frac{83}{300}$

НОЗ: 300.