(5/6-3/4)÷(2/3-4/9)＝（10/12-9/12）÷（6/9-4/9）＝1/12 ÷2/9＝1/12x9/2＝3/8
=(10/12－9/12)÷(6/9－4/9)=1/12÷2/9=1/12×9/2=3/8
