Let's do some magic

 

I used to be a magician. Every time I tried to pull a rabbit out of the hat he pulled me in instead. Anyway, let's attempt to do a trick. Below there are six cards - A  B  C  D  E  F.

Now select a number from any of the cards. You can write it down if you wish but don't do it near the computer monitor in case I see it. 

Have you chosen a number from any card? Good. 

Now tell me (in the comments box below) ALL the cards on which your number appears. For example say "C, E and F".

I've never tried this trick before, so with your co-operation it might work and I'll get the rabbit out of the hat.