2002又2003分之2002
=(2002*2003+2002)/2003
=2002*(2003+1)/2003
=2002*2004/2003
2002除以2002又2003分之2002
=2002/(2002*2004/2003)
=2002*2003/(2002*2004)
=2003/2004
2002又2003分之2002
=(2002*2003+2002)/2003
=2002*(2003+1)/2003
=2002*2004/2003
2002除以2002又2003分之2002
=2002/(2002*2004/2003)
=2002*2003/(2002*2004)
=2003/2004