On page 110 of Professor Stewart’s Casebook of Mathematical Mysteries, he shows a neat visual way of calculating the GCD (Greatest common denominator, aka HCF, Highest common factor. Given a box with sides of two different lengths, draw squares from the lesser side until you can draw no more. Then continue from the corner the other direction. The smallest square has edge length of the GCD!Continue reading “Euclid’s Doodle – and writing a visualization with Matplotlib”
There’s an old math trick that goes like so – choose any number… say 171…. add the digits and subtract.
171-9 = 162
Take its sum of digits and subtract them…
162 – 9 = 153
Take its sum of digits and subtract them… Continue reading “Analyzing Scott Flansburg’s Nines Trick”
Thousands of years ago, probably around the invention of the wheel, and before the time of Solomon, humans must have been measuring various objects… calculating some distances, and wondering, is there a better way to measure how far around the outside of a wheel is compared to its diameter? Continue reading “Neural Networks Part 2: Learning Pi”
Kilometers, Centimeters… microfarads, farads… They units are all a multiple of 10, but that doesn’t make them that much easier as you are first learning them. What is 1.09km in cm? or 1205cm in km? With a quick jotted down note card you can very quickly see what any commonly used metric unit converts to!
Today we did some up-cycling of political ad signs. After elections these generally go in the trash, but Talent Maker City had a public event to build some cool stuff out of these corrugated plastic boards!
Looking for a fun way to hand out candies at your local harvest fair? In this howto I show how to use a wood frame and old computer/printer parts to build a robot candy thrower: