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a quick math challenge
12-31-2013, 05:38 PM
Post: #15
RE: a quick math challenge
(12-31-2013 03:03 PM)Curlytop Wrote:  Can anybody explain why this works for 7 (and 13)?
\[ \begin{align}
1000&\equiv&6 (7) \\
&\equiv&-1 (7) \\
\end{align} \]
\[ \begin{align}
1000&\equiv&12 (13)\\
&\equiv&-1(13) \\
\end{align} \]
\[ \begin{align}
123,456,789&=&123\times1000^2+456\times1000+789 \\
&\equiv&123\times(-1)^2+456\times(-1)+789 (7) \\
&\equiv&123-456+789 (7) \\
\end{align} \]

Cheers
Thomas
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Messages In This Thread
a quick math challenge - Don Shepherd - 12-27-2013, 05:03 AM
RE: a quick math challenge - Han - 12-27-2013, 05:12 AM
RE: a quick math challenge - Don Shepherd - 12-27-2013, 12:47 PM
RE: a quick math challenge - Don Shepherd - 12-27-2013, 04:43 PM
RE: a quick math challenge - Paul Dale - 12-27-2013, 10:53 PM
RE: a quick math challenge - Les_Koller - 12-28-2013, 10:06 PM
RE: a quick math challenge - Waon Shinyoe - 12-29-2013, 02:19 PM
RE: a quick math challenge - Thomas Klemm - 12-29-2013, 03:37 PM
RE: a quick math challenge - aurelio - 12-29-2013, 06:31 PM
RE: a quick math challenge - Curlytop - 12-31-2013, 03:03 PM
RE: a quick math challenge - Thomas Klemm - 12-31-2013 05:38 PM
RE: a quick math challenge - Curlytop - 12-31-2013, 03:05 PM
RE: a quick math challenge - Curlytop - 12-31-2013, 07:25 PM



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