A student talked about Kaprekar’s constant (6174) during their my favorite presentation. Really cool. Steps (from wikipedia): Take any four-digit number, using at least two different digits. (Leading zeros are allowed.) Arrange the digits in descending and then in ascending … Continue reading
My son was given this lizard as a big brother gift (can’t find online link to product, but here’s a similar toy). Thoughts? Original Size Size After 2 Day Soak Before Measurements Left image Length: 905 pixels Width (between front … Continue reading
See also: World’s Greatest Drag Race 1 (with lesson) World’s Greatest Drag Race 2 Classroom action from my 180 photos blog Drag race page on 101qs.com
Part 1 and Part 2. There have been a couple of questions regarding the validity of my measuring process. The one that irked me the most was the fact that I had never measured the weight of the wafers of … Continue reading
So things have gone a bit crazy lately. While on summer vacation, this happened: All for a blog post that I wrote in February. (My previous high for views in one day was 299.) In the original post where my … Continue reading
2^86 is largest known pwr of 2 that does not contain 0.What about other digits?Does each non-zero digit occur inf often among the pwrs of 2? — James Tanton (@jamestanton) March 6, 2013 Interesting. The Intro to Programming Students gave … Continue reading
Number theory nugget: 357686312646216567629137 is a prime number which remains prime after removing any number of digits from the left side! — Maths World UK (@MathsWorldUK) March 4, 2013 Otherwise known as left-truncating primes with every suffix prime and no … Continue reading
[edit 8/20/13: New post with more data on the weights of Oreos and Double Stuf Oreos.] [edit 8/21/13: And Part 3.] Are Double Stuf Oreos really double stuffed? Some disagreement here: Chris Danielson in part 1 2 and 3 versus Chris Lusto in part 1 and 2. … Continue reading
How far away is the meteor from this security camera when it explodes?
Our baby is teething and while I was at the pharmacy, I saw a homeopathic remedy for teething babies with the following ingredients: Belladonna, aka Deadly Nightshade, has what percentage of alkaloids? 0.0000000000003% or 3 x 10^-13% Or if we … Continue reading