I had in mind three different digits chosen from 1 to 8 and I whispered the product of the three to Proddy and the sum of the three to Addy. I explained all this to them and our conversation then went as follows:
I: “Proddy, can you now work out what my three numbers are?”
I: “Now do you think that Addy will be able to work out what my numbers are?”
Proddy: “No, he will not be able to work them out.”
Addy: “Now I know what the numbers are!”
If you can evaluate the triplet - you are as gifted as ADDY!
Source: Old Enigma puzzle; attributed to Susan Denham