This article is based on a brilliant essay in Quanta magazine, behind which lies a lovely story of a mathematical discovery. I take the essay a little further and describe an algorithm we posted on arxiv to increase the speed of the calculation even further (though not as fast as the fastest method there is). You … Read More “Tales of Karatsuba” »

# Category: Recreational Math

Another week, another Manjul Bhargava delight. Arithmetic is usually taught in base 10. We have 10 unique symbols (0,1,2,3,4,5,6,7,8,9) and a place value system with the lowest value being , the next being , the next being and so on. So a number like . So far so good, but you could do this with … Read More “Modulo arithmetic & cards” »

Continuing our saga, trying to be intellectually honest, while a little prurient (Look It Up!, to adopt a recent political slogan), let’s look at the ridiculous “measured” correlation in point 3 of this public post. Let’s call it the PPP-GDP correlation! The scatter graph with data is displayed below Does it make sense? As in … Read More “p-‘s and q-‘s redux” »

Another Wednesday, another session of Manjul Bhargava’s entertaining and instructive class at the National Museum of Mathematics, in New York City. This time, the topic was that of rhythmic combinations and their connection to mathematics. As the sentence itself suggests, combinations of rhythms lead to combinatorial arithmetic – the notions of Fibonacci numbers and Pascal’s … Read More “Math, Rhythmic patterns & A Card Trick” »

I spent a pleasant evening at the National Museum of Mathematics this week – the first session of a semester long program of lecture demonstrations about mathematics and magic. The instructor is Manjul Bhargava, the famous Princeton mathematician. I thought the ideas were worth discussing in a more public forum, so I resolved to demonstrate … Read More “Of Baby Hummers and clock arithmetic with Aryabhata and Archimedes” »

The Bakhshali manuscript is an artifact discovered in 1881, near the town of Peshawar (in then British India, but now in present-day Pakistan). It is beautifully described in an article in the online magazine of the American Mathematical Society and I spent a few hours fascinated by the description in the article (written excellently by … Read More “Bucking down to the Bakhshali manuscript” »

This calculation was inspired, a few years ago, by trying to find a simple way to explain the sum of the first natural numbers to my (then) twelve-year-old daughter, without the use of calculus. As many people know, the sum of the first natural numbers is found very easily, using the method that Gauss (apparently) … Read More “A simple sum” »