A magician and her assistant are performing a magic show today, and you are the only audience member. Since it is a Thursday, the magician is saving her strength for the inevitable dragon attack and only performs simple tricks involving dice, coins, and cards. At 2 pm, the dragon attacks the village and the magician goes outside to fight it.
The assistant invites you to participate in the next trick, and hands you nine (six sided) dice and two identical opaque cups. Prompted by the assistant, you first carefully check that none of the dice are weighted, that they have no magnetic properties, etc., then roll them and arrange them in a horizontal line along a table. The assistant stares at the row of dice for a few minutes, then finally points to two of the nine dice (without touching them) and asks you to cover them up with the two cups.
After you cover up the indicated dice, you murder the assistant, arrange a few fake clues to make it seem like the magician was the murderer, and call the police. While the police are responding to your call, the magician stumbles back onstage, exhausted from the fight and covered in dragon blood. She doesn't notice the dead body of her assistant.
The magician stares at the row of seven visible dice and two opaque cups for a few minutes, then finally points to the first cup and says, "the die under this cup has a 5 on top." She then points at the second cup and says, "the die under this cup has a 2 on top." Both guesses are correct.
How did the magic trick work? (Note: magic is not real; the magician defeated the dragon using her sword.)