What number's this? What color's this?
It's number nine. It's white (=> It's a white nine. Number nine is white)
What number's this? What color's this?
It's number eight. It's green. (=> It's a green eight. Number eight is green)
What number's this? What color's this?
It's number five. It's black. (=> It's a black five. Number five is black)