# How can 1 + 10 = 9?

1+10=9

How?

#### Ackbach

##### Indicium Physicus
Staff member
Re: New Theorem

1+10=9

How?
LHS octal, RHS decimal or hexadecimal?

#### mathmaniac

##### Well-known member
Re: New Theorem

LHS octal, RHS decimal or hexadecimal?
,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....

I + X = IX

#### mathbalarka

##### Well-known member
MHB Math Helper
Re: New Theorem

Nice, mathmaniac!

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)

#### Klaas van Aarsen

##### MHB Seeker
Staff member
Let G be the group ({1,9,10},+) with the following addition table.

 + 1 9 10 1 10 1 9 9 1 9 10 10 9 10 1

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

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