3/14-1 (целая) 8/21+5/7=???

3/14 - 1 8/21 + 5/7 = 9/42 - 1 16/42 + 30/42 = 9/42 - 58/42 + 30/42 = - 19/42

3\14-1 целая 8\21=3\14-29\21=9\42-58\42=9-58\42= - 7\6; - 7\6+5\7=7*7\7*6 - 6*5\6*7 = -49\42- 30\42= -1 целая 37\42