You're dealt a pair of aces. The dealer shows a 5. Split or play it as one hand? Basic strategy answers:
| Split ← | +0.6147 |
| Hit | +0.1565 |
| Double | +0.1260 |
| Stand | -0.1672 |
| You bust on the next card | 0.0% |
| Dealer 5 busts | 41.6% |
Split is not close: it beats Hit by 0.4582 per unit. Getting this one wrong costs $4.58 on a $10 bet, every single time. Across the 340 situations in this chart it ranks 33rd by expected value — better than 307 of them, worse than 32. Expected value is per unit staked, computed for multi-deck, dealer stands on soft 17, double after split allowed. The model and the code are published as data.
Two aces are worth 12 together — a terrible total. Split, and each ace becomes the start of a hand worth ~52% of a blackjack. Splitting aces is the single most profitable move in the game, against any dealer card, including a 5.