Math Tricks

[Steve Torres]

This one is fun to play on people:

Ask them to write down a four digit number with no repeating digits.

Example: 1234

Then take that number and leave space for four more entries as though you are going to do an addition problem that has a total of five four-digit numbers.

Example:
1234
____
____
____
+____

Then, tell them that you are going to take turns adding numbers to the equation and that you will guess the answer beforehand.

Now, without them seeing exactly what you are doing, add 19998 to the number they gave and put it as the answer that you "guessed".

Example:
1234
____
____
____
+____
21232

Tell them to again give you a non-repeating four-digit number and put it as the second entry.

Example:
1234
4321
____
____
+____
21232

Now here is the tricky part! Or should I say the trick part... Add your own four digit number this time making sure that the number you add would equal to 9 in each column.

Example:
1234
4321
5678
____
+____
21232

See how the second number and the third number will equal 9 in each column?

Repeat this one more time. Making sure that you tell them not to use the same number. It will always work.

Example:
1234
4321
5678
6587
+3412
-------
21232

Congratulations, you're a genius!