Blackjack Strategy When Splitting a Pair of Threes
Split: When the dealer has a 2, 3, 4, 5, 6 or 7 showing.
Hit: When the dealer has an 8, 9, 10 or Ace showing.
Why to split a pair of threes
Splitting threes is the strategy when the dealer has 2 though 7 showing. Basic blackjack assumes that you would then get two 13's because of the high probability in drawing tens. So it's best to try getting the dealer to bust. You then need to use hard hand or soft hand strategies after you do the split, but the mathematical odds in blackjack says to split a pair of threes in this case.
Why to hit a pair of threes
When the dealer has an eight or higher, then the strategy shifts to hitting with a pair of 3's and hope to get a powerful hand. The dealer is likely to draw a 10 card and get a powerful hand so there is only one thing to do to beat an 18 or higher.