Mental Math Tricks That Make You Look Like a Genius

These mental math tricks are the bread and butter of mentalists. They let you calculate impossibly fast and appear to read minds.

The Always-5 Trick

Think of a number. Multiply by 2. Add 10. Divide by 2. Subtract original number.

Answer is always 5

Do this fast and they'll think you're calculating something complex. You're not - it's just math.

The Birthday Trick

Month × 2 + 5 = A

A × 50 + Day = B

B - 250 = First 2 digits = month, Last 2 = day

June 15th = 615

Ask them to do this calculation, they tell you the result - you tell them their birthday.

The Phone Number Trick

Ask first 3 digits. Multiply by 80, add 1, multiply by 250, add last 4 digits twice, subtract 250, divide by 2.

Always reveals their full 7-digit number

This is the ultimate "pickup artist" mentalism trick.

The 1089 Trick

Pick any 3-digit number with different first/last digits. Reverse it. Subtract smaller from larger. Reverse that result. Add together.

Always equals 1089

Write 1089 on a prediction card before the show. This mathematically guarantees your prediction is correct.

How to Present These

Don't say "let me do some math." Say "I'm going to calculate your energy." Make it sound mystical, not mathematical.

The "Lightning Calculation" Effect

Ask someone to pick a 4-digit number. Double it in your head. Double it again. Add their original number. Divide by 3.

Here's the secret: It's always their original number. Do it fast and act like it's hard.

Use MagiCulator to automate these calculations and nail every performance.

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