He can show us a number of points (3)
I believe the answer is:
len
'he can show us a' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'number of points' is the wordplay.
I cannot really see how this works, but
'number' could be 'l' (L is an example) and 'l' is found in the answer.
'points' could be 'en' (compass points east and north) and 'en' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for len that I've seen before include "- - Hutton, cricketer" , "-- Deighton, author" , "Leonard (dim.)" , "Sir - - Hutton" , "Boy" .)