;[2-(5.55x1又3分之1-2又10分之7除以0.2)]除以0.9
=(2-(5.55*4/3-27/10*5))/0.9
=(2-22.2/3+27/2)*10/9
=31/2*10/9-22.2/3*10/9
=155/9-222/27
=(155*3-222)/27
=243/27
=9