Пошаговое объяснение:
(4 5/13+2 8/13)-(1 12/13+3 7/13) = 6 13/13 - 4 19/13 = 7 - 5 6/13 = 1 7/13
(4 5/13+2 8/13)-(1 12/13+3 7/13) = 1 7/13
1) 4 5/13 + 2 8/13 = 7
2) 1 12/13 + 3 7/13 = 4 19/13 = 5 6/13
3) 7 - 5 6/13 = 1 7/13
