[4-(5/8-1/2)]÷2/3 =(4-1/8)÷2/3=31/8÷2/3=93/165/6×3/4+5/6÷4 =5/6x3/4+5/6x1/4=5/6x(3/4+1/4)=5/6x1=5/6
【4-(5/8-4/8)】÷2/3=(4-1/8)x3/2=31/8x3/2=93/16=5又13/165/6x3/4+5/6x1/4=5/6x(3/4+1/4)=5/6x1=5/6