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# Posts

### October 30, 2014

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Ich bin ja nicht ganz sicher, ob ich das hier veröffentlichen soll, aber die App ist schon wirklich stark: PhotoMath. Im Prinzip handelt es sich dabei um einen Taschenrechner: Man muss Aufgaben nur noch mit der Kamera scannen und erhält dann das Ergebnis, inklusive Zwischenschritten, auf dem Display angezeigt: Im … Continue reading →
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This post, like many others I’ve read over the last day or so, is inspired by Rob Carter (@robcarter2012) who wrote this post on a similar topic. It’s been a joy to read the posts which have provided much needed respite from the negativity pedal in some areas, such as the dreaded secret teacher. 1: […]
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I’m guessing this was about 5 years ago. I was at an all-day workshop when a high school math teacher, sitting next to me, asked about the PoW (from mathforum.org) that I assign to my students. I happened to have an extra copy in my backpack and gave it to her. Dad’s Cookies [Problem #2959] Dad bakes some cookies. […]
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El pasado mes de mayo de 2014, durante el evento que sirvió como celebración del 50 aniversario de los estudios de Matemáticas en la Universidad de Granada, Juan Medina (uno de los integrantes de la mesa sobre Matemáticas y Redes Sociales que tuve el honor de moderar) habló durante su intervención (por cierto, aquí tenéis […]Entra en Gaussianos si quieres hacer algún comentario sobre este artículo, consultar entradas anteriores o enviarnos un mensaje.Construye […]
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Looking for a reliable Tuition Agency? Its the holiday period now, and many parents are looking to find a tutor for the next academic year. Please look no further, as Startutor is the best tuition agency in Singapore, winning hands … Continue reading →
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Our paper about evaluating statistics used for ABC model choice has just appeared in Series B! It somewhat paradoxical that it comes out just a few days after we submitted our paper on using random forests for Bayesian model choice, thus bypassing the need for selecting those summary statistics by incorporating all statistics available and […]
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On Quora, someone asked, "What are the chances of survival of individual chess pieces in average games?" Oliver Brennan answered …Tags: chess, survival rate
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2430 = 2 x 3 x 3 x 3 x 3 x 3 x 5.2430 is the number of unordered ways to write 1 as a sum of reciprocals of integers no larger than 18.2430 is 3300 in base 9.2430 is the sum of two powers of 3 (A055235).2430 is the product of all distinct numbers formed by permuting digits of 2430 (A061147).2430 is a number divisible by the square of the sum of its digits (A072081).2430 divides 9127 - 1.Source: What's Special About This Number
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Source: http://blogs.wsj.com/washwire/2014/10/23/a-broader-problem-than-uncs-scandal-grade-inflation/ The scandal at the University of North Carolina at Chapel Hill is principally about academic dishonesty. But it highlights an institutional failure at almost all American colleges that dissuades students from pursuing the best career possible. Some academic departments systematically inflate … Continue reading →
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This is a humorous math comic based on the popular brainteaser: How do we join 9 dots using 4 lines? (Hint: Think out of the box. See the solution here: Answer) However, Spiked Math has added a new twist to the … Continue reading →
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I just finished posting an opinion to a thread on FB that had this graphic with it. It began here: NBC Nightly News with Brian Williams Do you know how to do Common Core math? Confusion over the standards has some calling for their removal. NBC’s Rehema Ellis reports tonight. One reader had addressed me […]
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Gli uomini di solidi principi sono sempre un po’ difficili da far venire a patti. Le considerazioni più significative che si possono fare in merito, sono forse proprio di natura matematica: l’aggettivo “solido”, per i seguaci d’Euclide, si limita ad essere una chiara definizione delle dimensioni necessarie a definire il sostantivo accompagnato, ma nel mondo [...]
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(Click on the comic if you can't see the full image.) (C)Copyright 2014, C. Burke.Secant you will find what Man was Not Meant to Know.
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So the first few years of my teaching career were pretty rocky.  Classroom management became a big focus, and I worked hard to strengthen that area.  While addressing the whole group, I had to start giving kids clear and direct instructions about whatever task that they are doing, and cracked down hard on any side conversations or […]
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alexyar: shadowpeoplearejerks: The more I realize the pedagogy in Hatcher is REALLY BAD. I still love the exercises and examples it has, but as a teaching tool it’s really sketchy and unreliable.  For example: Compare Hatcher’s proof that homotopy equivalent maps induce equivalent homomorphisms of homology groups to Massey’s.  Cubical homology though. Just…why. Seconded on Cubical homology; but of course you all know that the preferred construction of homology is as homotopy of […]
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by Gordon Hull Judge Richard Posner’s well-known application of law and economics to privacy yields results that appear, well, ideological. First, he considers what individuals do with informational privacy. What is an interest in privacy of information, he asks? Well, it’s an interest in enforcing an information asymmetry in markets....
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This is the current installment of the monthly series “Game Theory in the News.” My hope is to highlight stories that can be used as case studies in the classroom, both so students can see how to apply game theory and so teachers can make class material easier to relate to. You can get these […]
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DefinitionRecall the definition of the Geometric distribution of probabilities.Assume that we conduct a sequence of independent random experiments - Bernoulli trials with the probability of SUCCESS p - with the goal to reach the first SUCCESS. The number of trials to achieve this goal is, obviously, a random variable. The distribution of probabilities of this random variable is called Geometric.Formula forDistribution of ProbabilitiesRecall from a previous lecture the formula for the […]
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The Geometric distribution of probabilities is related to Bernoulli trials. It's definition is based on a concept of the first SUCCESS - the number of experiments needed to reach the first SUCCESSful result of Bernoulli trials. In theory, if FAILURE occurs time after time (which is not impossible if the probability of FAILURE is not zero), the number of experiments needed to reach the first SUCCESS can be unlimitedly largeWe will analyze the behavior of this number, more precisely, we will […]
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I was out of my classroom yesterday, attending an AP Stats workshop with my coworker and friend, Dianna Hazelton.  Upon my return, per the usual, I learned that students struggled with the assignment I left for them.  Naturally, it would seem that the most important task to be completed today was to address their issues with yesterday’s […]
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I taught the Mathalicious lesson “Not so Fast” yesterday, as I wrap up my unit on linear equations. I learned a lot about what my students understand, and gained a new perspective on how to teach linear equations. The lesson builds off of this information, from Virginia. I’ll let you go to the Mathalicious site to […]
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'Mathematics is the science that uses easy words for hard ideas.' ~ Edward Kasner The 303rd day of the year; there are 303 different bipartite graphs with 8 vertices. *What's Special About This Number 303 primes are below 2000. * Derek OrrEVENTS1613 Kepler married his second wife (the ﬁrst died of typhus). She was ﬁfth on his slate of eleven candidates. The story that he used astrology in the choice is doubtful.*VFR Kepler married the 24-year-old Susanna Reuttinger. He wrote that she, "won […]
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Segnalo ai colleghi docenti una eccellente infografica animata sulla respirazione, che può fungere da utile risorsa educativa a scuola.L'autrice è Eleanor Lutz, una talentuosa designer che vive e lavora a Seattle. Laureata in biologia molecolare ha anche svolto attività di ricerca. Gestisce Tabletop Whale, un originale blog di illustrazioni scientifiche.L'infografica citata illustra efficacemente tre modi di respirare, riferiti a due classi di vertebrati (mammiferi, nello specifico […]
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I’m having a great time at a workshop on Biological and Bio-Inspired Information Theory in Banff, Canada. You can see videos of the talks online. There have been lots of good talks so far, but this one really blew my mind: • Naftali Tishby, Sensing and acting under information constraints—a principled approach to biology and […]
Editor's Pick

### October 29, 2014

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Two of the barriers that students must overcome in the course of their math studies are fractions and algebra. Recently Heinemann published a textbook that makes it a lot easier for students to scale the algebra wall. The title is Transition to Algebra. It starts off in lesson 1 with exploring number tricks the kinds that I first learned about when I read W.W. Sawyer's Mathematician's Delight in 1972. A simple example is shown here in this video produced by Heinemann. I highly recommend this […]
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This post, which is on my new site here: http://www.numbersandshapes.net/?p=2520 shows how a cubic equation can be solved by origami.  This is not a new result by any means, but it’s hard to find a simple proof of how the
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Your password must contain a pound of flesh. No blood, nor less nor more, but just a pound of flesh. Your password must contain all passwords which do not contain themselves. Your password must contain any letter of the alphabet save the second. NOT THE BEES! NOT THE BEES! Your password must contain a reminder […]
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updated theorem
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A colleague recently used the word 'gimmicks' in reference to some of the ideas I share on this website. I got a bit defensive but I think it raises an important point. I'm well aware that role of teachers is to impart knowledge. I'm paid to fill children's minds with mathematics. I need no equipment, no facilities, no tools - I just need my brain, my voice and an audience. I haven't lost sight
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Yesterday's algebra class was great. We definitely fulfilled my goal of having more fun in math class. The night before last I had read an article linking curiosity with increased learning and engagement. Then yesterday's class illustrated that point perfectly.We are finishing up our unit on graphing linear equations. There are many resources available online to support this concept, so many that it was very difficult to choose. I used Dan's stacking cups. Me being me, I made a handout.I was so […]