Today is the presentation day, I still haven’t decided on which puzzle to present. I have redo my slides for at least three times by now. But, after long thought, and few hours of skipping class, I choose to use this Sum and Product puzzle.

It’s a math type of puzzle, and it is really a classic one, if you don’t believe me, see how somebody like Dijkstra was trying (and successfully) to write his solution to this problem in 70′s.

There are two integers x and y. x,y > 1 and x + y < 20. P is told the product while S is told the sum. Then this dialogue takes place:

- P: I don’t know what x and y are.
- S: I knew you wouldn’t know.
- P: But now I do know.
- S: And so do I!

Anyway, I published my presentation here.. too bad that I couldn’t embed it directly here.. https://docs.google.com/present/view?id=dcxs4x42_907sf6w5ck