(3/4+1/20)*1/2=(15/20+1/20)*1/2=16/20*1/2=16/40=0.4
(7/12-1/3)*16/19=(7/12-4/12)*16/19=3/12*16/19=3/3*4/19=12/57
(7 3/5-2 4/15)*9/32=(38/5-34/15)*9/32=(114/15-34/15)*9/32=80/15*9/32=80/5*3/32=16/1*3/32=3/2=1.5
(11/24+1/6)*1 3/5=(11/24+4/24)*8/5=15/24/*8/5=15/3*1/5=3/3*1=1
(5 1/2+2 3/5)*5/9=(11/2+13/5)*5/9=(55/10+26/10)*5/9=81/10*5/9=81/2*1/9=9/2*1=4.5
(7-2 5/16)*4/25=(7-37/16)*4/25=(6 16/16-37/16)*4/25=(112/16-37/16)*4/25=75/16*4/25=75/4*1/25=3/4*1=3/4