Dealers busting cards. The dealers face up card will affect most of your decisions. If the dealer is showing a 4, 5, or 6, you should know that they are commonly called 'dealer busting cards', and these cards offer an added opportunity in the game. In this case the best for you is to double down or split where you wouldn't normally.
Basically, if the dealer is showing one of these cards, it's not a bad idea to assume they have a card with a value of 10 as their hole card.If we take that assumption one step further, we realize the dealer is likely holding either a 14, 15, or 16.Since we know the dealer must draw cards until they reach seventeen, we know they would have to hit a 14, 15, or 16.Since we can presume (not with perfect confidence by any means) that the dealer will also draw a 10-value card, the totals of 14, 15, or 16 are likely to cause the dealer to bust.