Blackjack table

Hard 9 against a dealer 3 is a standard double in 6-deck blackjack with double allowed on any first two cards, since it has positive expectation.

Hard 16 against a dealer 7 is basic-strategy hit, since the dealer likely has 17 or better and standing wins too rarely. Doubling is legal but would be wrong here.

Hard 17 against a dealer 2 is a stand in basic strategy; hitting risks busting and doubling is not favorable.

Hard 20 against a dealer ten is a very strong hand; standing is the optimal basic strategy play, and splitting tens is worse in expectation.

Hard 20 against a dealer 9 is a strong made hand, and basic strategy says to stand rather than split tens or double.

Hard 16 against a dealer 10 (dealer has already peeked and has no blackjack): basic strategy is to hit, since standing loses more often in expectation than hitting, and no surrender is available.

Hard 18 against a dealer 10 is a stand by basic strategy; hitting risks busting too often and has lower expected value.

Hard 15 against a dealer ten is a losing spot either way, and with no surrender available basic strategy says hit. Doubling is incorrect here, and the dealer standing on soft 17 does not change this.

Hard 17 against a dealer ten is a stand in basic strategy, since hitting busts too often and rarely improves the hand enough to beat the dealer.

Soft 17 against a dealer ten is a hit by basic strategy; standing on 17 is weaker here, and doubling is not recommended against a ten.

Soft 18 against a dealer 10 is a hit under basic strategy, since standing on 18 loses more often than hitting a soft hand that can't bust on one card.

Soft 20 (A, 6, A, 2) against a dealer Jd is a very strong hand; standing is clearly optimal since hitting risks lowering the total.

Soft 15 against a dealer 7 (stand on all 17s): basic strategy says hit. Doubling is only correct against dealer 4-6, so hitting is the better play.

Hard 15 (4, A, K counted as 15) against a dealer 7 is a weak hand; basic strategy says stand on 15 vs 7 through 6 only, but versus a 7 the correct play is to hit since dealer 7 is a made hand of 17 more often. Hitting is the standard play for hard 15 vs 7 or higher.

Hard 20 against a dealer ten is a strong made hand; basic strategy says stand, since splitting tens or doubling has lower expected value.

Hard 5 against a dealer 6: basic strategy says hit. Doubling on a total this low is not favorable, so hit and take another card.

A hard 7 against a dealer 6 is far too weak to stand on, and doubling is not legal with three cards, so hitting is the correct play.

Hard 17 against a dealer 6 is a stand, since the dealer is likely to bust and hitting risks busting with little upside.

A hard 20 is a very strong hand against a dealer 4. Standing is the basic strategy play, and splitting tens is worse in expectation.

Hard 12 against a dealer 5 is a basic strategy stand, since the dealer busts often with a 5 up and hitting risks busting a stiff hand.

Hard 20 against a dealer 9 is a strong made hand; standing is correct basic strategy, and splitting tens is worse in expectation.

Hard 10 against a dealer 5 is a strong doubling spot, since the dealer is likely to bust or finish weak and a 10-value card gives me 20.

Hard 9 against a dealer 3 is a standard double in 6-deck blackjack with double allowed on any two cards, giving the best expected value.

Basic strategy for hard 12 against a dealer 3 is to hit; standing is only correct against 4 through 6, and doubling is not recommended on this total.

Hard 17 against a dealer 3 is a stand; the dealer is likely to bust or finish below 17, and hitting risks busting on most cards.

Hard 20 against a dealer 7 is a strong hand, so standing is correct. Splitting tens or doubling gives up expected value.