Putting two and two together and looking in the dustbin (7)
I believe the answer is:
totting
'putting' is the definition.
The answer and definition can be both to do with communicating as well as being present participle verbs.
Maybe you can see a link between them that I can't see?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for totting that I've seen before include "Adding up, aggregating" , "Determining the sum" .)