80 a) -8+(-3)= -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 +oo b) 15+ (-6)= +8 5 6 7 8 9 10 11 12 13 14 15 16 c) -2-6= d) 4+6= -11 -10 -9 -8 -7 -6 -5 -4-3-2-1 0 +8 +oo 0 1 2 3 4 5 6 7 8 9 10 11​