You're dealt a pair of 5s. The dealer shows a 9. Split or play it as one hand? Basic strategy answers:
| Double ← | +0.1443 |
| Hit | +0.1165 |
| Split | -0.5183 |
| Stand | -0.5432 |
| You bust on the next card | 0.0% |
| Dealer 9 busts | 22.8% |
Double beats Hit by 0.0278 per unit staked. Small, but it is the same small edge in every shoe you ever play — and it compounds over a lifetime of hands. Across the 340 situations in this chart it ranks 117th by expected value — better than 223 of them, worse than 116. 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.
A pair of 5s is really a hard 10 — one of the best doubling totals in the game. Splitting would create two hands starting from 5, the worst possible start. Against a 9, play it as 10: double down and press your edge.