`a_)`
`328/435 xx 468/432 xx 435/164 xx 432/984 xx 164/468`
`= (328/435 xx 435/164) xx (468/432 xx 164/468) xx 432/984`
`= 328/164 xx 164/432 xx 432/984`
`= (328 xx 164 xx 432)/(164 xx 432 xx 984)`
`= 328/984`
`= 1/3`
`b_)`
`2000/2001 xx 2002/2003 xx 2001/2002 xx 2003/2004 xx 2006/2000`
`= (2000/2001 xx 2006/2000) xx (2002/2003 xx 2001/2002) xx 2003/2004`
`= 2006/2001 xx 2001/2003 xx 2003/2004`
`= (2006 xx 2001 xx 2003)/(2001 xx 2003 xx 2004)`
`= 2006/2004`
`= 1003/1002`