1-1/2×【3×(-2/3)的2次方-(-1)的4次方】+1/4÷(-1/2)的2次方=1-1/2x(3x4/9-1)+1/4÷1/4=1-1/2x(4/3-1)+1=2-1/2x1/3=2-1/6=1又5/6
