Are they seeing how many tokens there are? (8)
I believe the answer is:
counters
'are they' is the definition.
The definition suggests a plural noun which matches the answer.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for counters that I've seen before include "Opposes the surfaces in shops?" , "chips" , "Tables for conducting retail business" , "Horizontal surfaces on which business is transacted" , "Argues in reply, parries" .)