How to Do a Cool Mathematical Mind Reading Trick

Last Updated: April 27, 2022

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

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
Ask them to pick a number in their mind from 0 to 9. ( Let's say 2 ).
2
Tell them to double the number. ( 2+2=4 ).

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3
Tell them to add five to the new number. ( 4+5=9 ).
4
Tell them to multiply the answer by five. ( 9*5=45 ).
5
Now tell them to remember the answer. ( 45 ).
6
Ask them to pick another number from 0 to 9. ( in this case 4 )
7
Ask them to add this number to their answer. ( 45+4=49 ).
8
Ask them to tell you the answer. ( 49 ).
9
Listen to it carefully and then in your mind subtract 25 from the total. ( 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 ).

Method 2

Method 2 of 2:

Mind Reading Number Trick

1
Understand the math behind this trick. 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).
2
Ham this trick up with magician's patter.
- 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.
3
Perform the trick:
- 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
Make your own magic number trick. 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".

Community Q&A

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.
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!
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.