1) 285 3/5 : 14 = 1428/5 * 1/14 = 102/5

2) 102/5-1 23/30=102/5-53/30=612/30-53/30=559/30

3) 559/30+13/50=2795/150+39/150=2834/150

4) 24 2/5-10 23/100=122/5-1023/100=2440/100-1023/100=1417/100

5) 7/12*2834/150=7/6*1417/150=9919/900

6) 9919/900:1417/100=9919/900*100/1417=7/9

7) 11 2/5+7/9=57/5+7/9=513/45+35/45=548/45=12 8/45