-8+(+9) = -8 + 9 = 1
+8+(-9) = 8 - 9 = -1
+12+(-15) = 12 - 15 = -3
-13+(+18) = -13 + 18 = 5
-2+(+18) = -2 + 18 = 16
+25+(-32) = 25 - 32 = -7
-8+(+9) = -8 + 9 = 1
+8+(-9) = 8 - 9 = -1
+12+(-15) = 12 - 15 = -3
-13+(+18) = -13 + 18 = 5
-2+(+18) = -2 + 18 = 16
+25+(-32) = 25 - 32 = -7