Hat & Hare

First 5 tricks · No. 2

The 1089 Prediction

A mathematical mentalism classic. They choose a random number; you predicted the result before they started.

Category
Mentalism
Level
Beginner
Learn it in
About 10 minutes
Difficulty

Draft. Awaiting review by our resident magician.

  • TODO: Review the book-test variation and patter
  • TODO: Add a recommended mentalism book for learners to continue with

The effect: what they see

Your friend invents a three-digit number and does some quick arithmetic on their own. The answer they arrive at matches a prediction that was sealed before they began.

What you need

  • Paper and a pen for your friend
  • An envelope with your sealed prediction
  • Optional, for the book-test version, any book you can prepare in advance

The method

No matter which number they choose, the answer is always 1089.

  1. Before you start, write 1089 on a slip of paper and seal it in an envelope. Hand the envelope to someone to hold.
  2. Ask your friend to write down any three-digit number where the first and last digits differ by at least two. (So 742 is fine, 747 is not.)
  3. Have them reverse it and write that number underneath. (742 becomes 247.)
  4. Subtract the smaller from the larger. (742 − 247 = 495.)
  5. Have them reverse the answer and add the two together. (495 + 594 = 1089.)
  6. Open the envelope. It matches.

Performance & patter

Arithmetic is the weak point of this trick. Nobody gasps at subtraction. So keep the math out of the spotlight and the choices in it.

Suggested patter: “I want you to invent a number nobody could guess. Not your birthday, not your house number. Something completely random.”

Turn your back while they work, so it’s clear you can’t see the paper. Hand them a calculator if they want one. Every bit of “fairness” you give them makes the ending stronger.

When they have their final number, don’t ask them to say it. Ask them to think of it, and then reveal your prediction.

Common mistakes

  • Not checking the first and last digits. If they’re equal (like 747), the trick fails. Explain the rule casually, as if you’re just making it “harder to guess.”
  • Doing it twice. The answer never changes. Once is all you get with the same audience.
  • Making it a math lesson. Don’t watch them calculate. Don’t explain why it works.

Where to learn more

Origin. Traditional mathematical principle, widely published in puzzle books and beginners' mentalism.

  • Mark Wilson's Complete Course in Magic by Mark Wilson