Question

Efetue:
6+4-6+9-9
-7+5-8+7-5
-3+5+3-2+2+1
-6+10+1-4+6
10-6+3-3-10-1
15-8+4-4+8-15

Answer 1

6+4-6+9-9 = 10-6+9-9 = 4+9-9 = 4
-7+5-8+7-5 = -2-8+7-5 = -10+7-5 = -3-5 = -8
-3+5+3-2+2+1 = 2+3-2+2+1 = 5-2+2+1 = 3+2+1 = 6
-6+10+1-4+6 = 4+1-4+6 = 5-4+6 = 1+6 = 7
10-6+3-3-10-1 = 4+3-3-10-1 = 7-3-10-1 = 4-3-10-1 = 1-10-1 = -10
15-8+4-4+8-15 = 7+4-4+8-15 = 11-4+8-15 = 7+8-15 = 15-15 = 0