Помогите пожалуйста 4/6 * 17/21+17/21 * 5/6

Ответ:

1 3/14

$\frac{4}{6} \times \frac{17}{21} + \frac{17}{21} \times \frac{5}{6}$

$\frac{4}{6} \times \frac{17}{21} = \frac{2}{3} \times \frac{17}{21} = \frac{34}{63}$

$\frac{17}{21} \times \frac{5}{6} = \frac{85}{126}$

$\frac{34}{63} + \frac{85}{126} = \frac{85}{126} + \frac{68}{126} = \frac{153}{126} = \frac{17}{14} = 1 \frac{3}{14}$