Math Magic Tricks

Math magic tricks are a fun way for kids to amaze their friends and also help them build some math skills along the way! 

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In this magic math trick, the math magician performs an instant calculation by quickly giving the sum of any four numbers a volunteer covers up!

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Are you ready? Great, Let's go.........

Preparation: Print the magic square. Ok, you printed the magic square, right. The first thing you need to know before I show you the trick is the square that you see on this page is special.  It’s actually called a magic square.  No kidding......Do you know why it’s called a magic square?  Notice what happens if you add up all the numbers in the top row.

24 + 11 + 3 + 20 + 7 = 65

Now take a look at the second row.

5 + 17 + 9 + 21 + 13 = 65

Can you guess what the numbers in the third row add up to? If you guessed 65, you’re right.  But there’s more……. The numbers in the first column add up to 65 also.

24 + 5 + 6 + 12 + 18 = 65

And the other two columns also add up to 65. And the two diagonals also add up to 65.  So that’s why it’s called a magic square.  65 is the magic number. Now back to our math magic trick. 

Performing The Trick:

• First you need to know what the magic number is for the square you are using.  For the square shown on this page, I already explained to you that the magic number is 65.
• Next, you figure out what number to subtract from 65 after the volunteer covers up any four numbers.
  

I'll show you how to find the number to subtract from 65 with a few examples. Look at the first example below.  Here you can see someone covered up four numbers at random with the green square.

As soon as they cover up four numbers with a square, in your mind you will extend a diagonal line, two numbers past the outside corner of the covered square.  In order to go over two numbers past the outside corner of the covered square, you can only go in one direction.

If you try to go diagonally in any other direction, you will not be able to go two numbers over.  Take a look at the picture below.  Notice that you can only extend the line two numbers in one direction.  The number you arrive at is 8.

This is the number that you subtract from 65.

65 - 8 = 57

So the numbers that are covered add up to 57.

Look back at the top picture and check for yourself to see that the numbers that are covered up, when added together are:

24 +11 + 5 + 17 = 57!

And there you have it.....

Have Fun With It!

By the way, I'll be adding some other magic squares for this magic trick so you can mix it up a bit.

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Here's another cool math trick that uses a square with 16 numbers. You can also check out lots of other magic tricks on the main Math Tricks page.

In case you want your students to learn more about magic square puzzles, check out magic square puzzles here. 

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Go to main Math Tricks page

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