Equity

Flop comes Kh-6h-2s. You're in the big blind with 9h-8h, having called a button raise. The button holds Kc-Jd for top pair; you have nothing made, just a flush draw. Four hearts show between your hand and the board, nine more sit in the deck. With two cards to come, nine outs is about 35% equity. Deal the turn and river a hundred times with no more betting and your flush lands in roughly 35 of them, win or lose the rest.

Now match equity to the decision. The pot is $100 before Villain bets $50. Calling $50 creates $200 total, so the price is 25%. A normal call buys only the next card, where nine outs are about 19%, so direct odds do not clear the price; the call needs realistic implied odds. If the $50 bet is all-in and calling guarantees both cards, the full 35% does clear 25%. Same draw, same price, different access to future cards.

The trap is reading 35% as the number for every flop decision. It assumes both cards arrive with no more betting. When another turn decision remains, position, future sizing, and who holds the betting lead decide how much equity you realize. Beginners also miscount outs up front. Count a card that pairs the board and hands Villain trips as clean, and a big draw turns into an expensive one.