Today is the 5th of April 2013. It’s a rare-ish moment in time, where a nice pattern is created. It’s also fairly rare that the trick works for both Americans and us Brits! I resent the fact that they get to celebrate Pi day on the 14th of March as they write it 3/14 whereas we notate it the other way giving 14/3.
Anyway, today becomes 5/4/2013 for us and it uses 6 consecutive digits – 012345.
A little bit of thinking brings me to the next time this happens as being 4/5/2013. After that we have 5/3/2014, 3/5/2014 and finally for this decade 3/4/2015.
Continuing in this theme, the years 2103, 2104 and 2105 will have dates in a similar format – the rest of the slots taken up by the unused digits (5/4/2103 and 4/5/2013). Alongside these, 2130, 2140 and 2150 will also have a couple of dates each year that fit the pattern.
Moving on to 123465 combinations, this provides us with 2134, 2135, 2136, 2143, 2145, 2146, 2153, 2154, 2156, 2163, 2164 and 2165 that will fit the above observation.
7 digit runs are possible. A month with 30 days provides 30/6/2145 for a 0123456 combo.
Going backwards, 1/01/1987 is built from the digits within the numbers 7 8 9 10 and 11. That date also has a lovely bit of symmetry as the number 7 8 9 10 and 11 written backwards (with a bit of manipulation) create 1101987 which is 1/10/1987!
When I wrote this on Facebook earlier, a friend wrote that 8 9 10 11 and 12 creates 10/11/1982 which is pleasing too.
For an 8 digit run, we have to wait until 27/10/3456, Andrew also pointed that out. I worked out that 23/04/1765 would have been the last time this 8 digit run would have happened.
This was pointed out in an email from an American site earlier today. I like to find new ideas from all over the place for maths teaching.
In less dull number news, here’s Kit from earlier. (Balancing numbers with cats is a well known trick for distracting people from the dullness. Not that I find numbers dull. This is fascinating to me…)
We completed a cache today too as it was another calendar gap. GC3BKRE was the target for the day and we found it successfully. We now have 190 gaps remaining… but have filled 48% of it now.
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5th April 2013 @ 10:12 pm
I looked at a Geocaching site here in Mexico, and the first and only one I peeked at said 20 pesos could be found inside. Can the contents be anything? What kinds of things do you find inside over in the UK?
6th April 2013 @ 10:08 pm
Well generally very little of any value – the fun is that it takes you to places you’ve never been and you see things you probably wouldn’t have noticed otherwise! We do it mainly to get out of the house and have something different to do rather than gaining anything of value from it. Does that make sense?