1.look at the following numbers:
-6, 0, 6, 12
which pair of numbers has a sum of 0?
a: 6, 12
b: 0, 6
c: -6, 0
d: 6, -6

2.look at the following numbers:
-10, -5, 0, 5
which pair of numbers has a sum of 0? (5 points)
a: -10, 5
b: 0, 5
c: 5, -5
d: -5, 0