Răspuns:
7-(-10)+12= 7 + 10 + 12 = 17 + 12 = 29
11-2+8-4+21= 9 + 8 - 4 + 21 = 17 - 4 + 21 = 13 + 21 = 34
6-5+12-8+4= -1 + 12 - 8 + 4 = 11 - 8 + 4 = 3 + 4 = 7