The Museum of HP Calculators

HP Forum Archive 16

 OT - date digit challengeMessage #1 Posted by Don Shepherd on 6 Apr 2006, 10:56 a.m. OK guys, something light. Yesterday it was 01:23:45 6/7/89. Big deal. I liked 01:23:45 6/7/89 better anyhow. Now, for the challenge. What was the last date that had all odd number digits? When will the next date be with all odd digits?

 Re: OT - date digit challengeMessage #2 Posted by bill platt on 6 Apr 2006, 11:12 a.m.,in response to message #1 by Don Shepherd November 29, 2005 January 1, 2007

 Re: OT - date digit challengeMessage #3 Posted by Don Shepherd on 6 Apr 2006, 11:44 a.m.,in response to message #2 by bill platt Hey Bill, that's right if you only consider the 2 digit year. What if you consider the 4 digit year?

 Re: OT - date digit challengeMessage #4 Posted by bill platt on 6 Apr 2006, 11:54 a.m.,in response to message #3 by Don Shepherd There's no difference. Odd numbers are a function of the last digit. Or do you want all *digits* to be odd? In that case, you hav to go back to Nov 29, 1999 and forward to Jan 1, 3111!

 Re: OT - date digit challengeMessage #5 Posted by Don Shepherd on 6 Apr 2006, 12:03 p.m.,in response to message #4 by bill platt Yes, you are right, I didn't explain it well enough. I wanted all digits to be odd. Nov 19, 1999

 Re: OT - date digit challengeMessage #6 Posted by bill platt on 6 Apr 2006, 12:11 p.m.,in response to message #5 by Don Shepherd oh, roight. sorry. Now, same problem as before, except that if you add up all the digits, the sum must also be odd. (both of these answers are even). Edited: 6 Apr 2006, 12:13 p.m.

 Re: OT - date digit challengeMessage #7 Posted by Don Shepherd on 6 Apr 2006, 2:22 p.m.,in response to message #6 by bill platt Bill, you're a crafty guy! 11/9/1999 1/11/3111 Neither of which has ANYTHING to do with my teaching portfolio, which I'm supposed to be working on today.

Go back to the main exhibit hall