(1)=(3+1)/5+1/2=9/10
(2)=1-5/9-1/9=1/3
(3)=(4+6)/24*8+2/3=(10+2)/3=4
(4)=(5+1)/9-1/2=2/3-1/2=1/6
(5)=1/4+1/8*6+1/18*6=1+1/3=4/3
(6)=1/6*(3/2)+2/9*(3/2)+3/4=1/4+3/4+1/3=4/3