I like the idea, and the composition is fine, if a little pedestrian; the focus is sharp, but what damages this for me is the uneven exposure and flash highlight on the table. I feel that the photograph would have benefitted from being cropped in closer, perhaps with a tighter arrangement of the cards.
Well lit and good, sharp focus. I'm not sure about the tie in between the cards and the number pi besides the obvious numerical reference. The circular chips are by far a stronger tie in with the callenge topic and would have been better if they played a larger role in the composition. I do love the way you've captured the rich color and texture of the wood, though.