100-25+50-75= 88+12-36=12= 450+150-250+350=

100 - 25 + 50 - 75
= 100 + 50 - 25 - 75
= 150 - 100
= 0

88 + 12 - 36 - 12 
= 88 + 12 - 12 - 36
= 88 - 36
= 52

450 + 150 - 250 + 350
= 450 + 150 + 350 - 250
= 950 - 250
= 700