Calculator Prediction

The Old Way

Most magicians perform this trick using their own phone, which immediately makes people suspicious. They rely on obvious apps or complex algorithms that look fake the moment a zero appears on the screen. When you use your own gear, the audience spends the whole time looking for a hidden button or a trick app instead of enjoying the magic.

The Better Approach

The secret is using the spectator's phone and keeping the setup simple. By using their device, you remove the "it's an app" excuse entirely. You don't need a fancy algorithm; you just need to guide the math so the numbers grow naturally toward your target.

This method lets you control the outcome while the spectator feels like they are making every choice. Because you’re doing the math on their phone, they trust the result. You can even use this to predict things like the serial number on a borrowed bill or a specific phone number. It’s about managing the flow of the conversation so that by the time they see the final result, they’ve already forgotten how they got there.

About the Instructor

Julio Ribera is a Spanish magician who specializes in making close-up magic feel spontaneous. He focuses on practical, real-world routines that you can perform anywhere, anytime, using objects people already have in their pockets.

What's Included

• How to use a spectator's phone to remove suspicion
• Techniques for forcing any number during a calculation
• Tips on using this for serial number or phone number reveals
• Managing screen rotation and settings without looking like you're "working"
• How to justify the setup so the trick feels like a natural conversation

Frequently Asked Questions

Why is this version better than the app-based ones?
Using a spectator's phone makes the effect feel genuine. When the math happens on their screen, they can't blame "tech tricks," which makes the reveal much stronger.

Will this work if I'm not good at math?
You don't need to be a math genius. The routine is designed to be simple, and the spectator does the heavy lifting while you guide the process to your target number.

Can I perform this impromptu?
Yes. Since you're using their phone and basic calculator functions, you don't need to carry anything extra with you.