so the original equation was ?
ok. obviously you're having trouble adding -7 and + 1
-7 + 1 = -6, not 8. if you can't see this, rearrange it, put the +1 in front. we get:
1 - 7 = ? obviously the answer isn't 8! it's -6
if you still don't see it, draw it on a number line. if you start at the point labeled -7 and move 1 unit in the positive direction, you will end up at -6