7/25-4/15 3/10+1/6 2/5-11/30 3/8+7/20 1/6-1/7 5/9+7/15 3/8+19/56 19/45-7/18 1/4-1/8 11/14+8/21 11/20-5/12 8/9+7/54 5/6-17/21

7/25 - 4/15=21-20/75=1/75 3/10+1/6=9+5/30=14/30 2/5-11/30=12-11/30=1/30 3/8+7/20=15+14/40=29/40 1/6-1/7=7-6/42=1/42 5/9+7/15=25+21/45= 46/45=1_1/45 3/8+19/57=21+19/56=40/56=5/7 19/45-7/18=38-35/90=3/90=1=30 1/4-1/8=2-1/8=1/8 11/14+8/21=33-16/42==17/42 11/20-5/12=33-25/60=8/60 8/9+7/54=48+7/54=55/54=1_1/54 5/6-12/21=5/6-4/7=35-24/42=11/42 3/16+1/24=9+2/48=11/48 5/6-22/27=45-44/54=1/54