add the following.
1.(+9) + (+10) =?
2.(-7) + (-5) =?
3.(+5) + (-6) =?
4.(+2) + (+8) =?
5.(-1) + (+10) =?
6.(-3) + (-3) =?
7.(+4) + (-8) =?
8.(-8) + (+12) =?
9.(-11) + (+11) =?
10. 0 + (-9) =?
pa help po need ko na po ito bukas​