# mod not explained

• March 31st 2008, 11:49 PM
idontdomath
mod not explained
what is 3 to the power -1 (mod 29)?
• April 1st 2008, 02:01 AM
CaptainBlack
Quote:

Originally Posted by idontdomath
what is 3 to the power -1 (mod 29)?

You can think of modular arithmetic as clock arithmetic, so a number ${\rm{modulo}}~
29$
is the remainder when that number is divided by 29.

In this case we are looking for a number $N$ in $[0,28]$ such that:

$3N=29 \times k +1$

for some integer $k$

RonL
• April 1st 2008, 02:12 AM
angel.white
Quote:

Originally Posted by CaptainBlack
You can think of modular arithmetic as clock arithmetic, so a number ${\rm{modulo}}~
29$
is the remainder when that number is divided by 29.

In this case we are looking for a number $N$ in $[0,28]$ such that:

$3N=29 \times k +1$

for some integer $k$

RonL

That makes a lot more sense than what I was thinking (glad I kept my mouth shut ^_^)