I have an easy method for u dude.
All u have to do is this.
Eg:- 1. +3 - -4
In positive side, there are 3 sticks or balls or whatever, but I will use sticks. In negative side, there are 4 sticks. Then u have to cut down negative to positive.
+ -
||| - ||||
= - | (-1)
2. -7 + +15
+ -
|||||
||||| |||||||
|||||
= +|||||||| (+8)
