Sean sent me the following math trick...
"3529411764705882 can be multiplied by 1.5 merely by moving the digit 3
from the front of the number to the end"
Not recognizing the number I was looking at (hint: 6 / 17 ), I started experimenting... what's the smallest number for which this works ( 1176470588235294 ), etc.
A google check later brought me to the Ribbon Puzzle.
Dudeney's Canterbury Puzzles was a regular highlight of my childhood summers - there was a copy of it in my family's Canadian Cabin, and I would regularly pick it up and work at some of the problems.
Which in turn got me to thinking about Cyclic Numbers, and trying to work out from first principles how to determine if a repeating fraction is going to have the nice properties that you want? The denominator needs to be prime; 1/7 and 1/17 work, but 1/13 does not. So what's the rule?
Turns out that the key is that the denominator be a Full Reptend Prime.
No general method is known for finding full reptend primes.
Translation: I can stop there, then.
Indiana Jones travels to a remote village in Central America to track down Patriots 19-0 memorabilia
Awww, show a little backbone, wouldja?
Mary Kate Olsen claims executive privilege in face of subpoena.
"You can't travel at the speed of light in the dark!"