(2 7/20•3\5+1 2\5:1 3/4)•2\5:4/5
1) 2 7/20•3/5=47/20•3/5=141/100 2) 1 2/5:1 3/4=7/5•4/7=4/5 3) 141/100+4/5=141/100+80/100=221/100 4) 221/100•2/5=221/250 5) 221/250+5/4=221/200=1 21/200