1 8/13 13/42 = (13+8)/13 13/42 = 21/13 * 13/42 = 21/42 = 1/2
5 5/7 : 8/21 = (32/7) : (8/21) = (32/7) * (21/8) = 672/56 = 12
(1/2 + 12) : (8 1/8 + 3 1/2) = (1/2 + 12) : (65/8 + 7/2) = (1/2 + 12) : (81/8) = (25/2) : (81/8) = (25/2) * (8/81) = 200/162 = 100/81
Ответ: 100/81
1 8/13 13/42 = (13+8)/13 13/42 = 21/13 * 13/42 = 21/42 = 1/2
5 5/7 : 8/21 = (32/7) : (8/21) = (32/7) * (21/8) = 672/56 = 12
(1/2 + 12) : (8 1/8 + 3 1/2) = (1/2 + 12) : (65/8 + 7/2) = (1/2 + 12) : (81/8) = (25/2) : (81/8) = (25/2) * (8/81) = 200/162 = 100/81
Ответ: 100/81