[ohnonotthat]

The flopped flush is the easier of the two.

There are 50 unseen cards, so . . . 50x49x48/3! = 19,600 (possible flops)

There are 11 cards of your suit; you need three to flop, so . . . 11x10x9/3! = 165


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The figures for the flopped draw are done the same way but here we need 2 of your suit and one NOT of your suit (the inclusion-exclusion principle); if you don't do it this way you'll double count the flopped flushes. (In other words, you'll count them as both made hands AND flopped draws).

PM me if you want it explained in greater detail.