Editing Draw (poker) (section)

===Backdoor draw===
A '''backdoor draw''', or '''runner-runner draw''', is a drawing hand that needs to catch two outs to win. For example, a hand with three cards of the same suit has a ''backdoor flush draw'' because it needs two more cards of the suit. The probability <math>P_{rr}</math> of catching two outs with two cards to come is:

:<math>P_{rr} = \frac{\mathrm{outs}}{\mathrm{unseen}\,\,\mathrm{cards}} \times \frac{\mathrm{outs} - 1}{\mathrm{unseen}\,\,\mathrm{cards} - 1}</math>

For example, if after the [[Flop (poker)|flop]] in [[Texas hold 'em]], a player has a backdoor flush draw (e.g., three spades), the probability of catching two outs on the [[Turn (poker)|turn]] and [[River (poker)|river]] is (10 ÷ 47) × (9 ÷ 46) = 4.16 percent. Completing backdoor draws is generally unlikely; the probability of seeing two out of seven outs on the turn and river is roughly the same as completing a draw with only out on either the turn or the river (1/47 + 1/46 = 4.3%). A backdoor outside straight draw (such as J-10-9) is equally likely as a backdoor flush, but any other 3-card straight draw (such as J-8-7) is less likely than getting a specific card after the flop, calculated above.