11/13-3/8+2/13-1/8(11/13+2/13)-(3/8+1/8)=1-1/2=0.5
=(11/13+2/13)-(3/8+1/8)=1-1/2=1/2
(11/13+2/13)-(3/8+1/8)=1-4/8=1-1/2=1/2