1.8/9×1/3+2/3 =8/27+18/27=26/272.1除以(1/2+2/3)=1÷1=1 3. 5.5除以(1-1/8-2/3) =5.5÷(1/3-1/8)=5.5÷(8/24-3/24)=5.5÷5/24=5.5×24/5=1.1×24=26.45/12×2/3除以5/24=5/18×24/5=24/18=4/3 2/3除以(1/2-1/3)=2/3÷1/6=4