Найдите значение выражения:

1) 8 7/10 - (7 4/5-а) при а=6 1/3

2) 14 1/6 - (8 9/10-b) при b=5 2/3

3) a - (9 3/50 - 5 7/25) при a=7 1/2

4) (20 1/5-b) - 6 1/3 при b=11 2/15

8 7/10 - (7 4/5 - а) = 8 7/10 - (7 4/5 - 6 1/3) = 87/10 - (39/5 - 19/3) = 87/10 - (117-95) / 15 = 87/10 - 22/15 = (261-44) / 30 = 217/30 = 7 7/30

14 1/6 - (8 9/10 - б) = 14 1/6 - (8 9/10 - 5 2/3) = 85/6 - (89/10 - 17/3) = 85/6 - (267-170) / 30 = 85/6 - 97/30 = (425-97) / 30 = 328/30 = 10 28/30 = 10 14/15

а - (9 3/50 - 5 7/25) = 7 1/2 - (9 3/50 - 5 7/25) = 15/2 - (453/50 - 132/25) = 15/2 - (453-264) / 50 = 15/2 - 189/50 = (375-189) / 50 = 186/50 = 3 36/50 = 3 18/25

(20 1/5 - б) - 6 1/3 = (20 1/5 - 11 2/15) - 6 1/3 = (101/5 - 167/15) - 19/3 = (303-167) / 15 - 19/3 = 136/15 - 19/3 = (136-95) / 15 = 41/15 = 2 11/15