4分之1乘2003加2005乘25％加2004乘0.75
=4分之1乘（2003+2005）加2004乘0.75
=4分之1乘4008加2004乘0.75
=1002+1503
=2505
4除以5分之4减5分之4除以4减4又5分之4
=4*5/4-4/5*1/4-4-4/5
=5-4-4/5*(1/4+1)
=1-4/5*5/4
=1-1
=0