А) -5/6+(-1/2)=-5/6 - 1/2 = -5/6 - 3/6 = -8/6 = -1 1/3
Б) -3/4+(-3/10)= -3/4 - 3/10 = -15/20 - 6/20 = -21/20 = -1 1/20
В)-3/5+3/5 = 0
Г) -4/9+8/15= -20/45 + 24/45 = 4/45
Д) 3,1/4+(-8,2/3) = 3 1/4 - 8 2/3 = 3 3/12 - 8 8/12 = -5 5/12
Е) -12,3/8+(-4,11/12) = -12 3/8 - 4 11/12 = -12 9/24 - 4 22/24 = -16 31/24 = -17 7/24
Ж) -2,5/9+(-2,5/8) = -2 5/9 - 2 5/8 = -2 40/72 - 2 45/72 = -4 85/72 = -5 13/72
З)-6,7/12+7,4/9 =- 6 21/36 + 7 16/36 = 31/36