Instead of separate numbers in each cracker, put in a clue as to where to find the numbers, which can be in batches so you don't need so many crackers, and which are hidden round the room. You could complicate things by making the references cryptic clues. Also put in a forfeit to be paid by the loser of the cracker pull- say, drink a pint of creme de menthe and cider, sing a lewd ditty, or submit to being grilled by the Special Branch- to add to the fun.