Several years ago my wife bought poppers for new year’s eve and mine came with a little puzzle called the Mystery Number Calculator. You would have someone pick a number between1 and 63 and show them six cards with number grids on them and ask if their number was on the card. The magic would happen at the end as I would provide their number at the end. I converted the game into a google sheets and tonight I have it has html. Give it a try and there is an explanation of how it works if interested.