1) 3*1/8-(4*5/16+1*1/4)=-2*7/16
4*5/16+1*1/4=69+20/16=89/16
3*1/8-89/16=50-89/16=-39/16=-2*7/16
2) -7*3/5-(-4*2/16-5*2/3)=2*1/5
-4*2/15-5*2/3=-62-85/15=-147/15
147/15-7*3/5=147-114/15=33/15=3*11/5=2*1/5
3) -23*1/2-(5*3/4+2*7/20)=-31*3/5
5*3/4+2*7/20=115+47/20=162/20=81/10
-23*1/2-81/10=-235-81/10=-316/10=-158/5=-31*3/5
4) -1/3-(3*7/18-1*2/9)=-2*1/5
3*7/8-1*2/9=61-22/18=39/18=13/6
-1/3-13/6=-2-13/6=-15/6=-5/2=-2*1/5