13/25-1/8-8/25=13/25-8/25-1/8=1/5-1/8=3/40
13/25-8/25-1/8=5/25-1/8=1/5-1/8=8/40-5/40=3/40
13/25-1/8-8/25=13/25-8/25-1/8=1/5-1/8=8/40-5/40=3/40