Calculate best cover for worker's group (3,2)
I believe the answer is:
tot up
'calculate' is the definition.
'best cover for worker's group' is the wordplay.
I cannot really understand how this works, but
'for' could be 'to' (eg both can mean 'in the opinion of') and 'to' is found within the answer.
The remaining letters 'tup' is a valid word 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 tot up that I've seen before include "Do summer job" , "Reckon" , "Add together (driving offences)" , "Summate" , "Count" .)