1) 20:2 2/15=20: 32/15=20*15/32=300/32=9 12/32=9 3/8
2) 25 5/7:2 2/35=130/7 : 72/35=130/7 * 35/72=65/1 *5/36=325/36=9 1/36
3) 9 3/8 + 9 1/36=18+ 29/72=18 29/72
9+9=18
3/8+1/36=27/72+2/72=29/72
4) 20 7/9 : 4 2/5=187/9 : 22/5=187/9 * 5/22=935/198=4 143/198
5) 4 143/198 -5/9=4 143/198 - 110/198=4 33/198 = 4 1/6
6) 18 29/72 : 4 1/6=1325/72 : 25/6=1325/72 * 6/25=53/12=4 5/12