Twenty-One Outs Example

Pocket Cards Community Cards
Queen of Diamonds Jack of Diamonds Nine of Diamonds Four of Clubs Ten of Diamonds
"Outside Straight Flush Draw with Two Overcards"

You may have just Queen high at this point, but chances are it will improve. Your twenty-one outs include the King of Diamonds or Eight of Diamonds to make a straight flush, the other seven Diamonds to make a flush, the other three non-diamond Kings to make a straight, the other three non-diamond Eights to make a straight, the remaining three Queens to make a pair, or the remaining three Jacks to make a pair. 2+7+3+3+3+3 = 21 :) . The chance of improving that hand on the turn is 44.681%. Even if it doesn't hit on the turn, on the river it would be 45.652%. Your overall chance on the flop for the turn and river combined is 69.935%! This is one of those rare cases where even if they have a Ten, you'd still have the advantage over them on the flop due to the sheer number of outs you have to improve.