Ответ:
5/12•4= 20/12=1 2/3
3/7•49=147/7=21
5/8 :25= 5/8•25=5/200=1/40
3/14 :9=3/14•9=3/126=1/42
5: 5/19=5•19/5= 95/5=19
4: 16/25= 4•25/16=6 1/25