Math Tricks

[Gaijin]

Do you know any of calculation tricks.

Here is a one that I know.
Take any 3 digits number, where the first digit is higher then the last digit. (321)
You then subtract the reverse number from the first one. (321 - 123)
And then you tell me only the last number of your result and I will tell you the whole result.

How does this work (Click to View)

Example: 632 - 236 = 396
As you see the first number is 632, 6 is higher then the last (2)
When subtracting a 3 digit number with it's on value reversed, the result has always the same effect
Example: 632 - 236 = 396 | 3 + 6 = 9
Example: 772 - 277 = 495 | 4 + 5 = 9
Example: 482 - 284 = 198 | 1 + 8 = 9
As you can see every of the above 3 results has a 9 in the middle.
When a person tells you the last number only, you just need to calculate 9 - x and the result is the first number.
3 + 6 = 9

[nevets04]

When multiplying by 5's dive the number by 2 and multiply by 10. For example:
8 x 5 = 40
HOW?
8 / 2 = 4.0
4.0 x 10 = 40

When multiplying by 9's subtract 1 from the first digit(This is the first digit of the answer) then subtract that number from 9(This is the second digit) For example:
7 x 9 = 63
HOW?
7 - 1 = 6
9 - 6 = 3

[JDBar]

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36=666

[uber1337]

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36=666

Crap not again...I need an old priest and a young priest...MAY THE POWER OF CHRIST COMPEL YOU!!!

[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!

[Extasey]

Got this email 2 days ago. I removed all the pictures and ridiculous amounts of blank lines that people have decided make chain emails so much more appealing.

This is pretty neat.

DON'T CHEAT BY SCROLLING DOWN FIRST!
It takes less than a minute .
Work this out as you read .
Be sure you don't read the bottom until you've worked it out!
This is not one of those waste of time things, it's fun.

1. First of all, pick the number of times a week that you would like to have chocolate (more than once but less than 10)

2. Multiply this number by 2 (just to be bold)

3. Add 5

4. Multiply it by 50 -- I'll wait while you get the calculator

5. If you have already had your birthday this year add 1759 ...
If you haven't, add 1758.

6.. Now subtract the four digit year that you were born.

You should have a three digit number

The first digit of this was your original number
(i.e., how many times you want to have chocolate each week).

The next two numbers are

YOUR AGE! (Oh YES, it is!!!!!)

THIS IS THE ONLY YEAR (2009) IT WILL EVER WORK, SO SPREAD IT AROUND WHILE IT LASTS.
Chocolate
Calculator.