Hitting is keeping your current hand, whereas standing is taking another card in an effort to improve your hand. While splitting entails splittinrummy now appg a pair into two hands to be played separately, doubling down entails doubling your initial bet in return for being dealt one more card. The value of your hand, the dealer's upcard, and the chance of busting if you take an extra card all play a role in determining whether to hit or stand.