Question

Помогите пожалуйстааааа !!!????

Answer 1

17/21 - 1/7 = 17/21 - 3/21 = 14/21 = 2/3

5/12 + 14/15 = 25/60 + 56/60 = 81/60 = 27/20

7/12 - 2/15 = 35/60 - 8/60 = 27/60 = 9/20

8/15 - (5/21+1/7) = 8/15 - (5/21 + 3/21) = 8/15 - 8/21 = 56/105 - 40/105 = 16/105

(3/16 + 5/12) - 3/8 = (9/48 + 20/48) - 3/8 = 29/48 - 3/8 = 1/2 - 3/8 = 4/8 - 3/8 = 1/2

Answer 2

1)
$\frac{17}{21} - \frac{1}{7} = \frac{17 - 3}{21} = \frac{14}{21} = \frac{2}{3}$
2)
$\frac{5}{12} + \frac{2}{15} = \frac{25 + 8}{60} = \frac{33}{60} = \frac{11}{20}$
3)
$\frac{8}{15} - ( \frac{5}{21} + \frac{1}{7} ) = \frac{8}{15} - \frac{8}{21} = \frac{16}{105}$