Blackjack table

Basic strategy: hard 9 doubles against a dealer 4 (weak upcard, dealer likely to bust), giving extra EV versus hitting.

Basic strategy: hard 10 doubles against a dealer 2, since the dealer is weak and one more card likely gives 18-21.

Basic strategy: with 10 against a dealer ace (dealer peeks, so no blackjack), hitting is correct; standing loses far more often than hitting.

Hard 15 against a dealer ace is a strong loser; with no surrender available, basic strategy says hit despite the bust risk.

Hard 17 vs a dealer Ace: basic strategy is to stand, since hitting busts about 62% of the time and standing has the better expected value. Dealer peeked with no blackjack, so I stand on 17.

Hard 17 vs dealer 7 is a clear stand in basic strategy; hitting risks busting a made hand, and doubling on 17 has poor expected value.

Soft 18 vs dealer 5 is a basic-strategy double: the dealer's 5 is weak and drawing gives a chance to improve to 19-21 while standing leaves a mediocre total.

Hard 15 against a dealer 6 is a standing hand in basic strategy; the dealer's high bust probability makes hitting riskier than letting the dealer play out.

Hard 18 against a dealer 6 is a clear stand in basic strategy; doubling hard 18 is not profitable, and hitting risks busting a likely winning hand.

Hard 19 against a dealer 10 is a clear stand; hitting risks busting a very strong hand for negligible gain.

Hard 6 against a dealer 10 is a mandatory hit; doubling here would be far too risky with such a weak total.

Hard 16 against a dealer 10 is a losing hand either way, but hitting has a better expected value than standing; basic strategy calls for a hit here since surrender is unavailable.

Hard 17 against a dealer 10 is a standing hand; hitting risks busting with no meaningful gain since dealer 10 upcard only slightly favors hitting at 17 in EV terms but bust risk dominates.

Soft 17 (A-6) against a dealer 6 is a classic double: the dealer's weak upcard with high bust potential makes doubling for max value correct under basic strategy.

Hard 18 vs dealer 8 is a clear stand; hitting risks busting a made hand with only modest upside, and doubling is not justified.

Hard 19 against a dealer 8 is a strong standing hand; hitting or doubling would only risk a near-made hand for negligible gain.

Hard 16 against a dealer 7 is a basic-strategy hit: standing loses to a likely dealer 17, while drawing improves or pushes the expected value. Doubling is far too risky with 16.

Hard 17 against a dealer 7 is a stand per basic strategy; hitting risks busting with no meaningful gain.

Basic strategy: split 6s against a dealer 3 to avoid the weak 12 and improve expected value with two hands.

Hard 16 against a dealer 3 is a standing situation in basic strategy; the dealer's bust risk outweighs the chance of improving without busting. Doubling a 16 is far too risky.

Hard 16 vs a dealer 3 is a standard stand: the dealer has a high bust probability with a small upcard, and hitting 16 risks busting (~62%). Doubling a weak 16 is not profitable.

Hard 20 against a dealer 5 is a near-certain winner; standing maximizes EV since hitting, doubling, or splitting 20s would only destroy a dominant hand.

11 against a dealer 6 is a strong doubling spot: only a 10 gives the dealer a made pat hand, and one card on 11 has high expected value. Doubling maximizes profit in this favorable situation.

Soft 19 vs dealer 4 is a stand in S17 games; doubling is only marginally better vs 5/6 in H17, so standing maximizes EV here.

Hard 19 against a dealer 6 is a strong hand; standing wins the vast majority of the time and doubling risks ruining a near-winning total.

Hard 18 vs dealer King is a clear stand under basic strategy; hitting risks busting a made hand, and doubling is only for strong two-card totals.