20+x=100
x=80
50-x=14
x=36
25-x=14
x=11
x+70=100
x=30
100+x=1000
x=900
50-x=36
x=14
7+x=21
100-x=25
x=75
68+x=29
x=39
140+x=230
x=90
56-x+x=156
x=100
450-x=140
x=310
500+x=730
x=230
900+x=2300
x=1400