1) -7 + (-8)= -7-8=-(7+8) =-15
2)-0.38 + (-0,74)=-0,38-0,74=-(0,38+0,74)=-1,12
3)-1,8 + (-0,34)=-1,8-0,34=-(1,8+0,34)=-2,14
4) - 4 6/7 + (-2 3/7)=-4 6/7- 2 3/7= -(4 6/7 + 2 3/7) = -8 10/7 =-8 3/7 +1=-7 3/7
5)- 6 7/15 + (-8 3/10)= -6 7/15- 8 3/10 =-(6 7/15 + 8 3/10) =
=-(6 2*7/30 + 8 3*3/30 ) = - (6 14/30+ 8 9/30)= -14 23/30