I am thinking of a fiftydigit number divisible by 239, of which, each digit is the same, except the ones digit. What is the ones digit?
I thought: "hmm, I need to know about the first 49 digits, what if I break it into 7digit chunks. What's 1111111/239?"
Turns out it divides evenly.
So it will divide the first 49 digits evenly no matter what digit they are. The last digit must be a 0.

Posted by Jer
on 20050513 16:55:53 