How do you subtract negative and positive integers? give an example of positives, negatives, and both.

Given -3 and 5, combine them (subtract 3 from 5):    5 - 3 = 2

Given -3 and -5, combine them (both are -, so add them, and keep -):    - 8

Given 1, -2, 7, -9, combine them:  
First combine the positive numbers:  1+7 = 8, and -2-9 = -11

Then combine those two results:  8-11 = -3 (answer)

If you need further help, please share some specific examples of the problems you're working on.