How to Do a Cool Mathematical Mind Reading Trick

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Mathematical mind reading tricks are a great way to combine your mastery of math with a bit of magical fun.

Method 1
Method 1 of 2:

0 to 9

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You ask the spectator to pick a number from 0 to 9 in his/her head. Later on after some steps they pick another number from 0 to 9. After one more step they tell you the answer and you can tell them the two numbers they picked in the same order!

  1. ( Let's say 2 ).
  2. ( 2+2=4 ).
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  3. ( 4+5=9 ).
  4. ( 9*5=45 ).
  5. ( 45 ).
  6. ( in this case 4 )
  7. ( 45+4=49 ).
  8. ( 49 ).
  9. ( 49-25=24 )
  10. The first digit of the answer YOU get in your mind after subtracting 25 ( 24 ) is the first number they picked ( 2 ) and the second digit is the second number they picked ( 4 ).
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Method 2
Method 2 of 2:

Mind Reading Number Trick

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  1. Clearly no matter what you start with, the answer should come out the same (zero isn't allowed). You can see why this trick works by using a little bit of high school algebra; if you follow the instructions starting with the variable X instead of an actual number, you will see that X is eliminated by adding the example's number 17 (see below).
    • The "original number" could be anything you want---someone's age, or their favorite number--- just ask the crowd for suggestions. This will change the final outcome, so test beforehand.
    • Think of a number, any positive integer. Keep it small so you can do computations in your head.
    • Square it.
    • Add the result to your original number.
    • Divide by your original number.
    • Add, oh, how about 17.
    • Subtract your original number.
    • Divide by 6.
    • The number you are thinking of now is 3!
  4. Using this idea, you can make up your own mental math trick right on the spot. Just don't do anything too obvious, such as telling people to add 5, subtract their original number, and say "the number you are thinking of is 5".
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  • Question
    Will this blow my friend's mind?
    Community Answer
    It depends on which type of friend you have. If they are good at math, then you are at hard luck. If not, then this should surely surprise them.
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    Not Helpful 22 Helpful 73
  • Question
    How do I choose a number from 0-9?
    Community Answer
    Random number generator. Just go to Google, search random number generator, add the limits from 0 to 9, and then voila!
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    Not Helpful 23 Helpful 34
  • Question
    For the second one, must you always divide by six?
    Community Answer
    Yes, if you don't divide by 6, the answer will not always come out to 3.
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      Tips

      • It is important to tell them to pick a number between 0 and 9 ONLY.
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      • Here's the math behind this mind trick: the person picks a number X, then multiplies it by two and adds five. You get 2X+5. You then multiply the result by five, you get: 10X+25. Te person picks a new number Y and adds it to the result, you get: 10X+Y+25. When you secretly subtract 25, you're left with 10X+Y, in other words a number whose tens digit is X and the units digit is Y.
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      • If the answer you get after subtracting 25 is 1 then the first number they picked was 0 and the second number they picked was one.
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      Warnings

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      Things You'll Need

      • Someone to try it out with.
      • Quick and accurate ways to get the answer in your mind.

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      About This Article

      Article Summary X

      Cool mathematical mind reading tricks are a great way to entertain your friends. Ask someone to think of a number between 0 and 9. Then, tell them to double the number and add 5 to the new number. Using the new number, have them multiply it by 5. Now have them think of another number between 0 and 9 to add to their current number. At this point, have them tell you the answer. Once you know their final number, subtract 25 from it. The first digit of the answer you get is the first number they picked and the second digit is the second number they picked. To learn how to perform a more advanced mind-reading number trick, keep reading!

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        Dec 30, 2016

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