Set one plus one between 50 and 500 (4)
I believe the answer is:
laid
'set' is the definition.
(synonyms)
'one plus one between 50 and 500' is the wordplay.
'one plus one' becomes 'ai' (I can't explain this - if you can you should give a lot more credence to this answer).
'between' means one lot of letters goes inside another.
'50' becomes 'l' (Roman numeral).
'and' is a charade indicator (letters next to each other).
'500' becomes 'D' (Roman numeral for 500).
'l'+'d'='ld'
'ai' going inside 'ld' is 'LAID'.
Can you help me to learn more?
(Other definitions for laid that I've seen before include "Produced eggs" , "Wagered" , "Deposited" , "Put down like dial" , "Doze" .)