This'll take 2 seconds to fix probably, so no use filling out the form 
Code:
How do I make the function allow a specific amount of items in the set slot? If I do~
^ That works. But not the variable. Why?
Code:
code_language.skript:
function setCardsLeft(p: player, i: integer):
set slot 4 of {_p}'s current inventory to {_i} paper named "&8&m------=====[!]=====------" with lore "||&d&lCasino Deck ||&r||&8&m------=====[!]=====------"
code_language.skript:
set slot 4 of {_p}'s current inventory to 64 paper named "&8&m------=====[!]=====------" with lore "||&d&lCasino Deck ||&r||&8&m------=====[!]=====------"