8/9-[3/4-(7/16-1/4)]=8/9-[3/4-7/16+1/4)=8/9-[(3/4+1/4)-7/16]=8/9-[1-7/16]=8/9-9/16=128/144-81/144=47/144 1/13+12/13×(5/2-1/3)=1/13+12/13×5/2-12/13×1/3=1/13+30/13-4/13=27/13