Time passed and the fourth of July became a larger number (6)
I believe the answer is:
twenty
'a larger number' is the definition.
'twenty' can be an answer for 'number' (twenty is a kind of whole number). I am not sure about the 'a larger' bit.
'time passed and the fourth of july' is the wordplay.
'time' becomes 't' (abbreviation).
'passed' becomes 'went' (I've seen this in other clues).
'and' is a charade indicator (letters next to each other).
'the fourth of july' becomes 'y' (tth letter of 'july').
't'+'went'+'y'='TWENTY'
'became' acts as a link.
Can you help me to learn more?
(Other definitions for twenty that I've seen before include "No longer a teenager" , "One score" , "Figure" , "This twice denotes normal vision" , "made by Q on a light blue square" .)