# trick

This is a cool trick that will impress any kid or adult.

• Write the number 1089 on a piece of paper and fold it without telling anyone the number. This will be the number that will show your skill as a mind reader.
• Ask a person to pick any three digit number without telling you the number. The easiest is if they use a calculator. eg. 683
• Ask them to subtract the three digit number if you reverse the order of the digits   e.g. 683-386 =297
• Now add the three digit numer if you reverse the order of the digit. e.g. 297+792=1089

You will get the same number regardless what three digit number they pick. I show it by picking another randum number:

824
824-428=396
396+693=1089

It is important to note that if the last digit is greater that the first digit in the picked number, the result will be negative after the subtraction as you reverse the order of the degits. However this is not a problem as if you just follow normal mathematic rules in the addation, as adding a negative number make the operation a subtraction, you will also get to 1089…but with netative sign.

e.g.

379
379-973= -594
-594+(-495)=-594-495= –1089

So the result will always be  +/-  1089. So to make it 100% accurate you can write |x|=1089 on the paper as this is true mathematically as “absolute x” means that you don’t care if  x is positive or negative…the sign doesn’t matter.