calculating this odds... is it ok?

[Ivanizh]

i'm a medium new player at poker and i want to know if it is correct to calculate flush draw odds (when i need only the flush to win):

u hold:

5 /images/graemlins/spade.gif 6 /images/graemlins/spade.gif

and the flop:

K /images/graemlins/spade.gif J /images/graemlins/heart.gif 2 /images/graemlins/spade.gif

now my math operation is this:

i need 1 of the remaining 9 /images/graemlins/spade.gif of the deck:

9/47 + 9/46 = 837/2162

this is aprox. 0.39, now my chances to get the /images/graemlins/spade.gif are 39% aprox.

is it ok? or what is my mistake?