90-48=42
48+42=90
100-31=69
69+31=100
35+47=82
82-47=35
52+18=70
70-18=52
82-56=26
26+56=82
73-47=26
26+47=73
90-48=42
48+42=90
100-31=69
69+31=100
35+47=82
82-47=35
52+18=70
70-18=52
82-56=26
26+56=82
73-47=26
26+47=73