Here's some
stupid math tricks:
Number Transformation:
- Pick any number.
- Add 3.
- Multiply your result by 10.
- Multiply your result by your original number.
- Subtract 10.
- Divide by 10.
- Add 1.
- Divide by your original number.
- Subtract 3 from the number
- Subtract your original number.
The result is always 0 (zero).
Magic Number
- Pick a number between 1 and 9.
- Multiply this number by 2.
- Add 5.
- Multiply by 50.
- If you have already had your birthday this year, add 1750*. If you haven't had your birthday yet, add 1749*.
- Last step: Subtract the four digit year that you were born.
The first digit of the answer is the original number you chose. The remaining two digits represent your age.
*: given for the year 2000. Increase these values by one for each successive year.
Prime number trick
- Choose any prime number greater than 3
- Square that number
- Add 14
- Divide by 12
The remainder will always be 3.
Finding someone's age
- Ask the person to multiply the first number of his or her age by 5.
- Tell them to add 3.
- Now tell them to double this figure.
- Finally, have the person add the second number of his or her age to the figure and have them tell you their answer.
- Deduct 6 and you will have their age.