MHB Is 1 + 10 equal to 9 in this group?

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The discussion revolves around the unconventional equation 1 + 10 = 9, suggesting it holds true in specific mathematical contexts. Participants explore the idea of different number systems, such as octal and decimal, to explain this equation. One contributor humorously presents a theorem involving a group structure where the addition of 1 and 10 results in 9. The conversation highlights the playful nature of mathematical exploration and the flexibility of mathematical interpretations. Ultimately, the discussion showcases how humor and creativity can intersect with mathematical concepts.
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1+10=9

How?
 
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Re: New Theorem

mathmaniac said:
1+10=9

How?

LHS octal, RHS decimal or hexadecimal?
 
Re: New Theorem

Ackbach said:
LHS octal, RHS decimal or hexadecimal?

:confused:,what do you mean?

Oh you mean different number systems?Clever!

Since this is a chat room and this topic was nothing but a joke,I was just joking...Here is the answer

I + X = IX
 
Re: New Theorem

Nice, mathmaniac! (Giggle)

Here's mine : X can be cut down from the middle and separate the upper V and the lower V. Hence, X = 2 * V. Now, we see that it is an universal truth and consistent with any other mathematical axioms in Rome : 10 = 2 * 5 !
 
Last edited:
11=9 (mod 2)
 
Let G be the group ({1,9,10},+) with the following addition table.

[TABLE="class: grid, width: 50"]
[TR]
[TD="align: center"]+[/TD]
[TD="align: center"]1[/TD]
[TD="align: center"]9[/TD]
[TD="align: center"]10[/TD]
[/TR]
[TR]
[TD="align: center"]1[/TD]
[TD="align: center"]10[/TD]
[TD="align: center"]1[/TD]
[TD="align: center"]9[/TD]
[/TR]
[TR]
[TD="align: center"]9[/TD]
[TD="align: center"]1[/TD]
[TD="align: center"]9[/TD]
[TD="align: center"]10[/TD]
[/TR]
[TR]
[TD="align: center"]10[/TD]
[TD="align: center"]9[/TD]
[TD="align: center"]10[/TD]
[TD="align: center"]1[/TD]
[/TR]
[/TABLE]

Then $1+10=9. \qquad \blacksquare$

(Or alternatively, $G=\mathbb Z/2\mathbb Z$.)
 
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