I don't know how to do negative numbers I don't know how to add subtract multiply and divide them

I never really understood it either usually I just this (-3+7) as you can tell the (-3) is smaller so I just move it to the other side and I see it as 7-3 which is the basic math and when it get more complicated like 27 + (-87) I just do this 27 - (87) and I move the smaller # (27) to the left side and now I have - 87+27 and I change that to - 87 - (-27) which would equal - 60 it seems a bit complicated and like a lot of procedures but I tried to explain it as best as possible