Worked out the figures about mid-January indeed! (7)

I believe the answer is:
deduced
'worked out' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for deduced that I've seen before include "Arrived at by reasoning" , "Concluded" , "Inferred" , "Worked out by reasoning" , "Gathered" .)
