Kate Catherine Cooper births (freebmd)
March 1871 , Nottingham, 7b, 223
March 1871 Nottingham, 7b, 225
(Registered twice? or two the same name within a number of each other?)
On checking the original scan (on freebmd) I think the transcriber with page 223 has got it wrong.
It's 225.
Now you should be able to find them in the censuses.