а) (2 4/5 + 4 2/3)3 3/4 : 7 1/5
= (14/5 + 14/3) 15/4 : 36/5
= (42/15 + 70/15) 15/4 : 36/5
= 112/15 15/4 : 36/5
= 28 : 36/5
= 28 * 5/36
= 140/36
= 35/9

б) (4 2/3 - 3/7) 2 5/8 : 9 8/9
= (14/3 - 3/7) 21/8 : 89/9
= (98/21 - 27/21) 21/8 : 89/9
= 71/21 21/8 : 89/9
= 71/8 : 89/9
= 71/8 * 9/89
= 639/712

в) (4 4/5 : 1 1/5 - 1 1/2) 1 3/5
= (24/5 : 6/5 - 3/2) 8/5
= (24/5 5/6 - 3/2) 8/5
= (4 - 3/2) 8/5
= (8/2 - 3/2) 8/5
= 5/2 * 8/5
= 4

г) (4 3/5 + 1 1/3) : 8 9/10 7 1/3
= (23/5 + 4/3) : 79/10 22/3
= (115/25 + 20/15) : 79/10 22/3
= (345/75 + 100/75) : 79/10 22/3
= 445/75 : 79/10 22/3
= 445/75 10/79 22/3
= 890/237 22/3
= 1960/237
≈ 8.27

д) (3/7 - 1 1/3) 21/86 : 7 2/5
= (3/7 - 4/3) 21/86 : 37/5
= (15/35 - 124/86) 21/86 : 37/5
= (258/774 - 1016/946) 21/86 : 37/5
= (-758/946) * 21/86 : 37/5
= (-17958/946) : 37/5
= - 161622/946
≈ -170.96

е) (3/7 33/40 + 5/6) : 1 11/12
= (99/280 + 5/6) : 23/12
= (99/280 + 70/120) : 23/12
= (99/280 + 117/120) : 23/12
= (267/840) : 23/12
= 267/840 12/23
= 3564/9660
= 1188/3220
= 594/1610
= 297/805

ж) (6 7/12 - 3 17/36) 1/2 - 4 1/3 : 13/20
= (79/12 - 109/36) 1/2 - 13/3 : 13/20
= (222/36 - 109/36) 1/2 - 13/3 : 13/20
= 113/36 1/2 - 13/3 : 13/20
= 113/72 - 20/3
= 113/72 - 40/12
= (1133 - 4012)/72
= (339 - 480)/72
= -141/72
= -47/24

з) (1 11/24 + 13/36) 1 11/25 - 8/15 9/16
= (47/24 + 13/36) 136/25 - 72/120
= (2820/1440 + 520/1440) 136/25 - 9/20
= 3340/1440 136/25 - 9/20
= (3340 136)/(1440 25) - 9/20
= 453440/36000 - 9/20
= 22672/1800 - 9/20
= (22672 20)/(1800 20) - 162/1800
= 453440/36000 - 162/1800
= 15113/1200 - 3/33
= (15113 33)/1200 - 90/1200
= 498729/1200 - 90/1200
= 498639/1200
= 41553/100