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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,585

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: 92,372

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.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,585

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: 3,585

*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: 3,585

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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