m46patton2013 7/30+5/18=7*3/90+5*5/90=21/90+25/90=46/90=23/45
15/19+27/38=15*2/38+27/38=57/38=1 19/28=1 1/19
6/7-9/14=6*2/14-9/14=12/14-9/14=3/14
7/18-1/45=5*7/90-1*2/90=33/90=11/30