Ну и !?!?!? А какой вопрос????????
1) -4+(-7) = -11
2) -0,46+(-0,89) = -1,35
3) -2,3+(-0,86) = -3,16
4) -5 7/9 + (-3 4/9) = -52/9 + (-31/9) = (-52-31) / 9 = -83/9 = - 9 2/9
5) - 5/8 + (-11/12) = (-15-22) / 24 = -37/24 = - 1 13/24
6) -4 5/14+(-7 9/21)=-61/14 + (-156/21) = (-1281-2184) / 294 =-3465/294 =-11 231/294
8\15( 15\4-5\16н)-3\20(20\3м-40\9н)= 8\15*15\4-8\15*5\16н-3\20*20\3м+3\20*40\9н=2-1\6н-м+2\3н=1\2н+2-м