You're dealt a pair of 5s. The dealer shows a 7. Split or play it as one hand? Basic strategy answers:
| Double ← | +0.3924 |
| Hit | +0.2569 |
| Split | -0.1918 |
| Stand | -0.4754 |
| You bust on the next card | 0.0% |
| Dealer 7 busts | 26.2% |
Double is worth 0.1355 more per unit than Hit. On a $10 bet that is $1.35 handed over every time you get it wrong. Across the 340 situations in this chart it ranks 68th by expected value — better than 272 of them, worse than 67. 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 7, play it as 10: double down and press your edge.