1)0,5:1,25=0,4
2)7/5:1 4/7=7/5*7/11=49/55
3)2/5+49/55=22/55+49/55=71/55
4)71/55-3/11=71/55-15/55=56/55
5)56/55*3=168/55
---------------------
6)1,5+1/4=1,5+0,25=1,75=1 3/4
7)1 3/4:18 1/3=7/4*3/55=21/220
----------------
8)168/55:21/220=168/55*220/21=8*4=32