2003/2004*2*2005
=2003/2004*（2004+1）*2
=2003/2004*2004*2+2003/2004*1*2
=4006+2003/1002
=4007又1001/1002
2003/2004*2*2005 简便方法怎么算?今天就要的啊!
2003/2004*2*2005
=2003/2004*（2004+1）*2
=2003/2004*2004*2+2003/2004*1*2
=4006+2003/1002
=4007又1001/1002