100 - ___ = 100
100 - 0 = 100
100 - ___ = 20
100 - 80 = 20
40 + ___ = 100
40 + 60 = 100
100 - ___ = 50
100 - 50 = 50
90 + ___ = 100
90 + 10 = 100
100 - ___ = 80
100 - 20 = 80
60 + ___ = 100
60 + 40 = 100
100 - ___ = 50
100 - 50 = 50
