Coolgirl657657 1) 6+8 = 14; -1+3 = 2; -9-10 = -19
2) 9+5 = 14; 4-4 = 0; -6+11 = 5
3) -7.1+7.1 =0; -7.1-7.1= -14.2; 7.1+7.1 = 14.2

Porchy322 1) (+6)-(-8) = 14
(-1)-(-3) = 2
(-9)-(10) = -19
2) (+9)-(-5) = 14
(+4)-(+4) = 0
(-6)-(-11) = -17
3) (-7,1)-(-7,1) = 0
(-7,1)-(+7,1) = -14,2
(+7,1)-(-7,1) = 14,2