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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,588

If you know how a knight

moves in chess, you might

enjoy this little matrix I

just came up with that has

to do with adding and

subtracting the number 3.

*Last edited by John E. Franklin (2010-02-07 15:07:13)*

**igloo** **myrtilles** **fourmis**

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 103,826

Hi John;

We only have one problem here. If you take the tour 1 - 8 - 5 - 2 - 9 ? Only works if we are using modular arithmetic.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **A number by itself is useful, but it is far more useful to know how accurate or certain that number is.**

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,588

Yes, I'm only looking at the last digit.

Like 1 - 8 = 11 - 8 = 3

**igloo** **myrtilles** **fourmis**

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,588

*Last edited by John E. Franklin (2010-02-14 14:05:51)*

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,588

Here's something I kind of like for adding numbers together

in my head, or on paper if you come up with shortcut

drawings and dots...

By putting the zero and five at the

center points, some very

nice symmetry occurs in adding

pairs of numbers together.

There are 55 adding problems we

remember as children, 36 that are

not trivial (without 1 or 0 in them).

Try them all on this for fun in

geometric groups such as diagonals,

poles, longest diagonals, doubles,

horizontal beams, 5 added to any number,

etc.

*Last edited by John E. Franklin (2010-02-17 04:57:03)*

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