Question

90 divided by -7.2 (I want to see how do you do it

Answer 1

See, its 90/-7.2
So, first multiply and divide by -1 so the equation doesn't get affected
Then it comes, 
= -90/7.2
Now remove the point and multiply with 10
= 900/72
Thereofore, the resulting answer would be 12.5

Answer 2

You could type it into a calculator, or use the by hand way.