а) 1\8+1\10+1\4= 5/40 + 4/40 + 10/40 = 19/40
б) 1\6+1\10+1\15= 5/30 + 3/30 + 2/30 = 10/30 = 1/3
в)3\20+1\5+1\6= 9/60 + 12/60 + 10/60 = 31/60
г)3\7+1\6+5\14= 18/42 + 7/42 + 15/42= 40/42 = 20/21
д)3\4+4\25+7\20= 75/100 + 16/100 + 35/100 = 126/100 = 1 26/100 = 1 13/50
е)1\2+1\3+1\9= 9/18 + 6/18 + 2/18 = 17/18