It values low cards (2–6) at +1, neutral cards (7-9) at 0 and high cards (10–Ace) at -1. Players can estimate the proportion of high to low cards left in the deck & modifrummy teen pattiy their bets by keeping a running count of these values as cards are dealt. While it's not against the law, casinos do not support card counting and may request that players who are suspected of doing so leave the area. Not only does card counting need a great deal of practice, but it also demands a high degree of skill and concentration.