When adding or substracting with negatives(-), keep these things in mind:
(+) + (+) = (+)
(-) + (-) = (-)
(+) + (-) = ( take the sign of the LARGEST NUMBER and substract)
EX: 8 + (-3) = 5
(+) - (-) = [ double minus becomes a (+)]
EX: 10 - (-5) = 5