Crossword Genius

Somebody you start to count on (3)

Ross

I believe the answer is:

one

I'm a little stuck... Click here to teach me more about this clue!

'somebody' is the definition.
(I know this)

'you start to count on' is the wordplay.
I cannot really see how this works, but
'on' is within the answer.
A single letter 'e' remains which might be clued in a way I don't see.
This explanation may well be incorrect...

Can you help me to learn more?

(Other definitions for one that I've seen before include "Sole; identical" , "Single person or thing" , "doesn't count for much" , "Figure" , "Lowest cardinal number" .)

I've seen this clue in the Evening Standard.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.