I recently found myself creating a set of regular polygons for a worksheet. I used GeoGebra to create them, and then free-handed the zoom in order to get them consistently sized. This led me to wonder what “consistently sized” would mean when it comes to polygons. There are six basic values of a regular n-gon:…
Author: Clio
Reflections on Fractions
I was reading an article on fractions, waiting for students to show up for after-school tutoring. One of them asked me what I was reading, so I told him. He groaned. I asked him what his least favorite topic in mathematics was, and he told me it was fractions. I nodded, saying that I reckoned…
Three Card Monty Hall
Imagine we are playing a game of cards. In this game, there are only three cards in the deck: An Ace and two Kings. I will deal you one card, and I will keep the other two. You win if, at the end of the round, you are holding the Ace. You are not allowed…
Thoughts about the Cracks
An adult friend is getting tested to see if she has a formal neurological problem that would account for her struggles with mathematics. She asked how it could be that she might make it all the way through public education without being tested for such a learning disability (LD). Here were my thoughts; keep in…
Forms of the Quadratic: Terminology
Because mathematical terminology developed piecemeal over time, there are many inconsistencies which prove to be a challenge to students. One of the more obvious examples is what is called the “standard form” of the quadratic. A quadratic equation has three common forms: \(ax^2 + bx + c = 0\) \(a(x – h)^2 + k =…
Slide rules and calculators
Several of my math teacher colleagues are of the opinion that calculators have destroyed math sense. I am not convinced that this is directly true: Calculators are a tool, nothing more. A few months ago, I saw a video by the mythically amazing Vi Hart which led me to an epiphany: Perhaps the problem isn’t…
MEYL: Q. 1194
This is my translation of Meyl’s 1878 proof that a triangular pyramid of balls will only have a square number of balls if the base side is two or forty-eight. “Solutions to questions posed in The New Annals: Question 1194.” A. J. J. Meyl, former artillary captain at the Hague, Nouvelles annales de mathématiques. Journal…
Lucas: Q. 1180
This is my translation of Lucas’s 1877 proof that a square pyramid of balls will only have a square number of balls if the base side is twenty-four. “Solutions to questions posed in The New Annals: Question 1180.” M. Édouard Lucas, Nouvelles annales de mathématiques. Journal des candidats aux écoles polytechnique et normale, second series,…
Gerono: Q. 1177
This is my translation of Gerono’s 1877 proof listing all the possible solutions (x, y) for the equation \(y^2 = x^3 + x^2 + x + 1\). “Solutions to questions posed in The New Annals: Question 1177.” MM. Gerono, Nouvelles annales de mathématiques. Journal des candidats aux écoles polytechnique et normale, second series, volume 16…
Pyramids and Squares
I have been spending my free time the last few days on the task of working backwards through three proofs in a 19th century French language mathematics journal. This started with a simple question in the G+ Mathematics community, posted by Jeremy Williams: “Who can find the largest tetrahedral number that is also a square?”…