Impress your friends and family with these math tricks. They are described in increasing order of difficulty (from minor to major numbers); even a small child can perform the number prediction one.
Steps
Method 1 of 3: Simple Number Prediction
Step 1. Prepare the makeup
Tell a friend that you are going to do a math trick and that he has to mentally do some calculations; at the end you will read his mind to find the final solution.
Step 2. Write the forecast
Pretend to concentrate intensely for a moment and then write the number 3 on a piece of paper; fold it in half without letting anyone see what you wrote.
Step 3. Ask your friend to write a number between 1 and 20
He doesn't have to tell you what his choice is and keep the paper to himself.
- Suppose, for example, that the interlocutor chose 4.
- This trick works with any number, but limiting the options to the range of 1 to 20 makes the friend less likely to make miscalculations.
Step 4. Ask him to add 1 to his number
Warn him not to nod or move his lips; all you need is your mental power.
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For example, if you chose 4, the process is 4 + 1 =
Step 5..
Step 5. Now ask him to double the result
Instruct him to multiply the new number he got earlier by 2.
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5 x 2 =
Step 10..
Step 6. Now you need to add 4
Bring your hands to his head and concentrate as you tell him to add 4 to the solution calculated so far.
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10 + 4 =
Step 14..
Step 7. Divide by 2
Announce that you are almost done, but that the number is too big for you and you can't see it; So tell him to cut it in half to make things easier.
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14 ÷ 2 =
Step 7..
Step 8. Subtract the starting number
Now ask the interlocutor to look at the sheet on which he wrote down the number he had chosen and to remove it from the solution of the last mathematical operation he performed.
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7 - 4 =
Step 3..
Step 9. Show your prediction
Tell him that you have finally succeeded in reading his mind. Ask him to announce the number he found, then unfold your paper and show the audience what you wrote. No matter what the starting number is, the solution is always 3.
Method 2 of 3: Guessing the Age
Step 1. Tell the person that you are going to guess their age
Tell her that you will use your math skills to read her mind; hand her a calculator in case she doesn't want to do the math in her head.
- This trick isn't very exciting with friends and classmates as you are likely to know their age.
- Choose an interlocutor who is at least 10 years old and no more than 99 years old.
Step 2. Ask him to multiply the first digit of his age by 5
Remind him to perform the calculations quietly and not to tell you his age.
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For example, if the individual is 32, he should consider the figure "3" and multiply it by 5. The solution is 3 x 5 =
Step 15..
Step 3. Add 4 to the solution
At this point the interlocutor must add the number 4 to the one he found previously.
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Considering the example: 15 + 4 =
Step 19..
Step 4. Tell him he must double the result
The new value must be multiplied by 2, ask him to let you know when he's done; if he is doing the math in his head, make sure he is sure of the result, as most people tend to make mistakes in this step.
19 x 2 = 38.
Step 5. Have him add up the second digit of his age
The next step in the "mind reading" process is to add the last digit of the age; inform the person that this is the last calculation they have to make.
Since you took a 32-year-old person as an example, the value to add is 2. The last number he calculated is 38, so the final solution is 38 + 2 = 40.
Step 6. Ask me to tell you the number it came to
Make sure you say it out loud so that everyone in the audience can hear it.
Step 7. Subtract 8 and announce its true age
Mentally proceed to the calculation and when you get the solution say it out loud.
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As for the example, 40 - 8 =
Step 32..
Step 8. Try some variations
If you do the trick more than once, people notice the math mechanism. Here are some variations to ensure the aura of mystery:
- Instead of adding 4 and subtracting (secretly) 8, you can add 3 and subtract 6 or add 2 and subtract 4 or even use the pair 25-50. Remember that you must always subtract twice as much as you add, because the expression is multiplied by 2.
- To really mix "the cards on the table" try this sequence: double the age, add 2, multiply by 5 and subtract 10. You must multiply by 2 and also by 5 to move the first digit of the age (the number 3 of the example) instead of the tens, the one that belongs to him.
Method 3 of 3: 37 Magical
Step 1. Give a volunteer a pencil and paper
This trick uses three-digit numbers, so most people don't want to do the math in mind. Notify the other party that they need to make a split online.
Step 2. Ask him to write the same number three times
He does not have to show you the paper, in order to show that you are not "cheating"; inform him that he must write down a number of three identical digits.
For example, he could write 222.
Step 3. Tell him to add up the digits
At this point he should consider them as individual numbers and find their sum.
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For example, 2 + 2 + 2 =
Step 6..
Step 4. The next step is to divide the larger number by the smaller
Ask him to find the quotient between the first three-digit number and the sum; give it some time to do this.
222 / 6 = 37.
Step 5. Announce that the number is 37
If the volunteer followed your instructions correctly and made no calculation errors, the solution is always 37.
