**Problem-Solving:**

**Look! Up in the Sky!
It's a Bird! It's a Plane!**

**No! It's SuperNumber:
6,174!**

**Today's
Snack:** Eat
six raisins, one apple, seven peanuts, and four oyster crackers to celebrate
our SuperNumber, 6,174. Drink water, too!

--------------------

**Supplies:**

**Scratch paper and pencil**

** **

Here is a weird, strange, odd,
peculiar fact of math: the number __6,174__ is ALWAYS the answer, no
matter what numbers you start off with, if you follow a particular process or
structure in subtraction.

So __6,174__ is the SUPER
NUMBER that CANNOT be DEFEATED. Hunhhhh?

Weird? Strange? Odd? Yes. So naturally, you want to
know how to do it:

1.
Select four different numbers from 0 to 9. Let's say you pick 7, 8, 2 and
3.

2. Now arrange them to make the largest number possible. So
you put the biggest number first, and the smallest number last: 8,732.

3. Now we're going to do a subtraction problem.
Underneath the 8,732, rearrange the numbers the opposite way, to make the
SMALLEST number possible: 2,378.

4. Subtract the smaller number from the larger number:

8,732

__- 2,378__

6,354

5. Now rearrange THAT number again, to make it as large
as possible: 6,543.

6.
And rearrange it yet again to make it as SMALL as possible: 3,456.

7.
Subtract again:

6,543

__- 3,456__

3,087

8. Do that same process again - rearrange those four
numbers into the largest number possible, and from it, subtract the smallest
number possible - even if there's a zero, include it:

8,730

__- 0,378__

8,352

9. And rearrange one more time into largest possible and
smallest possible:

8,532

__- 2,358__

__ __**6,174**

. . . and what do you know! There it is! Our SUPER
NUMBER!!!!

It
took us four subtractions, in this process, to come up with 6,174.

Now,
on scratch paper, YOU try it again, with four DIFFERENT numbers.

How
many subtractions does it take YOU to get to our SUPER NUMBER?

For
discussion: why on Earth do you think this works?

Guess
what? No one really knows, but 6,174 is the only number this works with.

It's
called Kaprekar's Mystery, because it was discovered by a mathematician named
Kaprekar from India. Read more about it:

http://plus.maths.org/content/os/issue38/features/nishiyama/index