1) 9/53-3/28=0.257-0.107=0.15 2) 7/20-0.15=0.35-0.15=0.2=1/5
1) 9/35-3/28=72/280 - 30/280 = 42/280 = 6/35 2) 7/20 - 6/35 = 49/140 - 24/140 = 25/140 = 5/28.