https://github.com/Kaggle/learntools/blob/3d21e2e21d08ec02a78fec15a4d8d71b66ebc816/learntools/python/blackjack.py#L58 Should be : `if (tot + 9) <= 21:` because 1pt has already been added in _tot_ for aces. Example: I have already 11pts without ace and I hit an Ace. _tot_ must get 10 pts (1 + 9) and not 11 (1+10) Here is the example I got during a simulation 