Not sure what you mean but here goes
BLUE said:
An up-card A will have a down-card 10 31% of the time ( 4 out 13). Why is the % different for the other cards?
When someone says a 10, in the language of blackjack, they mean a 10,J,Q or K, a total of 4 of the 13 types of cards. So you get 1 ace in 13, one 2 in 13, one 3 in 13 but 4 tens in 13. So 4/13 of cards being a 10 gives you a 31% shot but other cards or about 7.8%
ihate17