The Telephone Number Predictor Magic Trick

Young men sitting at table looking at calculator
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  • 01 of 05

    Setting Up the Trick

    Here's one of those mathematical oddities that somewhat masquerades as a magic trick. Your spectator, with a calculator in hand, performs a series of calculations. And surprise, at the end, he or she is looking at their telephone number. We walk you through the steps and at the end, display them all on a single page that you may print out.

    Secret: Some mathematical oddity. Ask a math whiz, not a magician.

    Ask your spectators to grab their calculators and enter the first three digits of their telephone numbers. Be sure that they enter the first three digits of their actual phone number, not the area code. As an example, we'll use the fictional phone number of 555-1212.

    Enter 555

    Continue to 2 of 5 below.
  • 02 of 05

    Multiply and Add

    Ask them to multiply by 80.

    555 x 80 = 44400

    Ask them to add 1.

    44400 + 1 = 44401

    Continue to 3 of 5 below.
  • 03 of 05

    Multiply and Add Again

    Ask them to multiply by 250.

    44401 x 250 = 11100250

    Ask them to add the last four digits of their telephone number. And then add the same number again.

    11100250 + 1212 = 11101462

    11101462 + 1212 = 11102674

    Continue to 4 of 5 below.
  • 04 of 05

    Subtract and Divide

    Ask them to subtract 250

    11102674 - 250 = 11102424

    Ask them to divide by 2. If they've done everything correctly, they'll be looking at their telephone number!

    45113 / 2 = 5551212

    Here are the steps again:

    Enter the first three digits of their phone number
    Multiply by 80
    Add 1
    Multiply by 250
    Add the last four digits of their telephone number.
    Add the last four digits of their telephone number again.
    Subtract 250
    Divide by 2

    Continue to 5 of 5 below.
  • 05 of 05

    The Full Trick

    Here are the steps in full again:

    1. Enter the first three digits of their phone number
    2. Multiply by 80
    3. Add 1
    4. Multiply by 250
    5. Add the last four digits of their telephone number.
    6. Add the last four digits of their telephone number again.
    7. Subtract 250
    8. Divide by 2