The 6174 Trick

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SOURCE: http://www.learn-with-math-games.com/math-tricks-for-kids.html

Math Skills: This trick is good for helping students practice four-digit subtraction.

What You Need: Piece of paper and pencil

Performing the Math Trick

• Have someone choose any four-digit number.  (At least one digit should be different from the other digits)
• Arrange the digits in order from largest to smallest and write that number down.

• Now have them reverse the digits of this number and subtract it from the last number they wrote down.

• After they subtract and get the answer, have them arrange the numbers from greatest to least if they are not already.
• Now have them subtract the reverse of this number from itself (same procedure as above).

• Keep repeating these same steps and they will soon arrive at the magic number: 6174!  

Not at the Magic Number yet, so they keep going.

And just like magic…..they will reach the Magic Number! (See below)

Pretty Cool!  It works every time.

Note: It might be a good idea to make sure they are doing the subtractions correctly, otherwise they may not get to the Magic Number.