1 2/9*3 4/7=11/9*25/7=4 23/63
12,1*2/11=121/10*2/11=11/5=2 1/5
3,8*1 2/7=38/10*9/7=342/70=4=31/35
(7 1/9-2 5/6)*0,54=(64/9-17/6)*54/100=(128/18-51/18)*54/100=77/18*54/100=
=231/100=2 31/100
5/16:0,125=5/16:125/1000=5/16*1000/125=1000/400=2 200/1000=2 1/5