deletions | additions       diff --git a/friends.tex b/friends.tex  index 267a8cf..324af52 100644  --- a/friends.tex  +++ b/friends.tex 
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\[  17=2 \times 7 + 3.   \]  The remainder, namely $3$, is the number interesting of interest  for our purpose. This is nothing but an application of division algorithm. Focus on the second clock, the one with $12$ hours, and suppose we want to find what is the $26^{th}$ hour. We have also in this case two tours around the clock and then the remainder is $2$, that is  \[  26=2 \times 12 + 2.