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Category Archives: math

Introducing Akshay

We are starting a new category of posts on Maths puzzles, being written by Akshay Gowrishankar, a 9th grader from Massachusetts, USA. He is a budding roboticist, enjoys math puzzles, and teaches a Middle School Math Olympiad class. His first post of the series is here.

Math Puzzle 1

For every positive integer starting from 2, Vinay divides the number by 2, and floors it (flooring a number means to take the largest integer that is less than or equal to that number). He keeps repeating the process until he gets 2 or 3, and categorizes as a 2 or a 3 based on […]

What if? [Q&A]

I had previously mentioned a technique called order-of-magnitude estimation that scientists of all stripes find extraordinarily useful, and Atul of Canara College asked me what that meant. One of the most important characteristics of doing science is that scientists look to work on problems that can be solved. There is no point in wasting years […]

Ludi Saeculares: the Transit of Venus

On June 5 (or June 6, depending on which time zone you are in) of 2012, Venus will be seen from the Earth passing over the disk of the Sun. This is not only a rare event, but also one which has been of great historical importance in figuring out how big the Solar System […]

Space Math [try it]

I came across this brilliant collection of math problems in a variety of practical settings in the context of space exploration and astronomy. It is a fantastic resource for teachers setting up realistic math problems. The site is called Space Math @ NASA. There is even a page with the problems sorted by NASA missions […]

distance to the Moon [try it]

How far is the Moon? You don’t have to look up the answer in a book. You can measure it yourself, and quite easily at that. You will need an accomplice however. For this, you will need some way to record the precise location of the Moon in the sky relative to the stars in […]

parallax [try it]

How do we know how far anything is? For nearby objects, we can pace off the distance, of course, but what about places we can’t walk to? How does your brain know that that door is 10 feet away without marking it off on a ruler? Suppose you are standing at point A (see figure) […]

alien communication [try it]

Back in 1974, a message was beamed out from the Arecibo radio telescope towards the globular cluster M13. The hope is that it will be intercepted by some alien civilization that will then study it and learn some basic things about us. The full message, encoded as a string of two distinct patterns, is given […]

exponential increase [try it]

Take a chess board and some rice. Put a grain of rice on the first square, Rook’s a1. Put two grains on the next one, Knight’s b1. Keep going down the row, doubling the grains at every square (4 on Bishop’s c1, 8 on King’s d1, etc), and continue the same way for row 2, […]

yasti yantra [Q&A]

Suhas of Poornaprajna PU College asks, what is the stick machine of Bhaskaracharya? I had no idea what it was until I looked it up online. There is a nice description in a report by S. Narvekar (Astronomical Instruments of Ancient India, IFToMM 2007) that describes a stick-like device that can be used to measure […]