# Math

• ## Most Topular Stories

• ### Which mathematician had the biggest gap between fame and contribution?

Computational Complexity
22 Mar 2015 | 7:35 pm
(I was going to call this entry  Who was the worst mathematician of all time? but Clyde Kruskal reminded me that its not (say) Goldbach's fault that his conjecture got so well known, in fact its a good thing! I'll come back to Goldbach later.) Would Hawking be as well known if he didn't have ALS?  I suspect that within Physics yes, but I doubt he would have had guest shots on ST:TNG, The Simpsons, Futurama, and The Big Bang Theory (I just checked the IDMB database- they don't mention Futurama but they do say he's a Capricorn. I find that appalling that they mention a Scientists…
• ### Mathematicians solve 60-year old-problem

Mathematics News -- ScienceDaily
23 Mar 2015 | 12:06 pm
A 60-year old maths problem first put forward by Nobel laureate Enrico Fermi has finally been solved. In 1955, a team of physicists, computer scientists and mathematicians led by Fermi used a computer for the first time to try and solve a numerical experiment. The outcome of the experiment wasn't what they were expecting, and the complexity of the problem underpinned the then new field of non-linear physics and paved the way for six decades of new thinking. Chaos theory, popularly referred to as the butterfly effect, is just one of the theories developed to try and solve the…
• ### A Few of My Favorite Spaces: The Cantor Set

Scientific American - Math
26 Mar 2015 | 5:30 am
Last month, I wrote about the -Base, a website that serves a similar function to the book Counterexamples in Topology. I'm teaching a topology class this semester, and it's been fun to revisit some... -- Read more on ScientificAmerican.com
• ### News Aplenty

Computational Complexity
25 Mar 2015 | 11:10 am
Both the Turing Award and the Abel Prize were announced this morning. MIT databases researcher Michael Stonebraker wins the ACM Turing Award. He developed INGRES one of the first relational databases. Stonebraker is the first Turing award winner since the prize went up to a cool million dollars. John Nash and Louis Nirenberg share this years Abel Prize “for striking and seminal contributions to the theory of nonlinear partial differential equations and its applications to geometric analysis.” This work on PDEs is completely independent from the equilibrium results that won Nash…
• ### Quantum compute this: Mathematicians build code to take on toughest of cyber attacks

Mathematics News -- ScienceDaily
26 Mar 2015 | 8:24 am
Mathematicians have designed an encryption code capable of fending off the phenomenal hacking power of a quantum computer. Using high-level number theory and cryptography, the researchers reworked an infamous old cipher called the knapsack code to create an online security system better prepared for future demands.
• ## MATH - Google News

• ### Choate to dedicate new math, computer science building - New Haven Register

26 Mar 2015 | 4:47 pm
Choate to dedicate new math, computer science buildingNew Haven RegisterWALLINGFORD >> Officials at Choate Rosemary Hall will dedicate a new math and computer science building Friday. The new Cameron and Edward Lanphier Center for Mathematics and Computer Science open early last month after construction of the ...
• ### Ravens' John Urschel NFL Pro By Day, Math Wiz By Night - CBS Local

26 Mar 2015 | 1:39 pm
CBS LocalRavens' John Urschel NFL Pro By Day, Math Wiz By NightCBS LocalUrschel has three degrees in math including two masters. He graduated from Penn State in just three years with a perfect 4.0 and he's known to use his math skills to analyze the team's performance. “If Harbaugh is talking about something and it John Urschel Of Baltimore Ravens Balances Football With MathTech TimesRavens Offensive Lineman John Urschel Explains His Mathematics PaperForbesall 3 news articles »
• ### Virginia awards $1.6M to boost teacher science, math - The Daily Progress 26 Mar 2015 | 10:27 am Cody EnterpriseVirginia awards$1.6M to boost teacher science, mathThe Daily ProgressRICHMOND — The Virginia Department of Education is awarding more than $1.6 million in grants to enhance teachers' knowledge of science and math and their ability to teach the subjects. The department said in a release that nine partnerships between ...Panhandle students tally wins at Regional Math Field DayHerald-Mail MediaSunset School Math NightCody EnterpriseMath Super Bowl played todayPorterville RecorderPost-Bulletin -SW News Mediaall 3,001 news articles » • ### Some Pick at Math in New York City Affordable-Housing Strategy - Wall Street Journal 26 Mar 2015 | 8:44 am Wall Street JournalSome Pick at Math in New York City Affordable-Housing StrategyWall Street JournalIn many neighborhoods, Mayor Bill de Blasio's plan to spur construction of affordable apartments by allowing developers to build towers may face an unusual problem in New York City: The rent is too low. City Hall plans to let developers build taller and more » • ### Front Row Education Is Changing The Way Math Is Taught In U.S. Elementary ... - Forbes 26 Mar 2015 | 8:32 am ForbesFront Row Education Is Changing The Way Math Is Taught In U.S. Elementary ForbesIn 2013, Sidharth Kakkar and Alexandr Kurilin had the opportunity to watch children learning math in an inner-city Baltimore school. For a month, they attended to school every day and worked with students. At night, they programmed to make an • ## Search for "math OR mathematics" • ### Jazz bigs Derrick Favors and Rudy Gobert need help from the line from Karl Malone and Mehmet Okur 26 Mar 2015 | 10:28 pm The Jazz don't have to look far in their rolodex to find the right guys to help Derrick and Rudy's free throw shooting woes Over the last season many people concerned with the Utah Jazz have been concerned with the free throw shooting. And there's good reason to be concerned. • ### Dominion announces$1.5 million in scholarships

26 Mar 2015 | 10:27 pm

• ## Let's Play Math!

• ### Education Bloggers: Share Your Post!

17 Mar 2015 | 10:06 am
[Image by Omar Omar (CC BY 2.0) via Flickr.] Please Note: We need volunteers to host future carnivals! See below for more information. If you are a homeschooler or classroom teacher, student or independent learner, or anyone else who writes about math, now is the time to send in your favorite blog post for next week’s Math Teachers at Play (MTaP) math education blog carnival. Click here to submit your blog post. Browse all the past editions of the Math Teachers at Play blog carnival Have you noticed a new math blogger on your block that you’d like to introduce to the rest of us? Feel…
• ### For the Curmudgeons: Vi Hart’s Anti-Pi Rant

14 Mar 2015 | 7:26 am
More about Tau: Happy Tau Day Get monthly math tips and activity ideas, and be the first to hear about new books, revisions, and sales or other promotions. Sign up for my Tabletop Academy Press Updates email list.
• ### Happy Birthday, General Relativity

14 Mar 2015 | 4:55 am
Don’t forget that Pi Day is also Albert Einstein’s birthday! And this year marks the 100th anniversary of his Theory of General Relativity. So Science Magazine has a special Einstein issue online, featuring this interactive comic: You may also enjoy: the Happy Birthday, Einstein! video series Happy Birthday, Einstein (Part 2) Happy Birthday, Einstein (Part 3) Happy Birthday, Einstein (Part 4) Albert Einstein’s math biography Math-related quotes from Albert Einstein Get monthly math tips and activity ideas, and be the first to hear about new books, revisions, and sales or…
• ### Pi: Who Needs That Many Digits?

13 Mar 2015 | 4:50 am
From Numberphile: Pi is famously calculated to trillions of digits – but Dr. James Grime says 39 is enough. How you round it off makes a difference: An extra note from Dr. Grime: “Since pi39 ends in 0, you may think we could use pi38 instead, which has even fewer digits. Unfortunately, the rounding errors of pi38 are ten times larger than the rounding errors of pi39 — more than a hydrogen atom. So that extra decimal place makes a difference, even if it’s 0.” Get monthly math tips and activity ideas, and be the first to hear about new books, revisions, and sales…
• ### Pi and Buffon’s Matches

12 Mar 2015 | 9:29 am
From Numberphile: Dr Tony Padilla’s unique (and low budget) twist on the Buffon’s Needle experiment to learn the true value of Pi. For a kid-friendly version of this experiment, try throwing food: How to Calculate Pi by Throwing Frozen Hot Dogs Do you have a favorite family activity for celebrating Pi Day? I’d love to hear it! Get monthly math tips and activity ideas, and be the first to hear about new books, revisions, and sales or other promotions. Sign up for my Tabletop Academy Press Updates email list.
• ## Computational Complexity

• ### News Aplenty

25 Mar 2015 | 11:10 am
Both the Turing Award and the Abel Prize were announced this morning. MIT databases researcher Michael Stonebraker wins the ACM Turing Award. He developed INGRES one of the first relational databases. Stonebraker is the first Turing award winner since the prize went up to a cool million dollars. John Nash and Louis Nirenberg share this years Abel Prize “for striking and seminal contributions to the theory of nonlinear partial differential equations and its applications to geometric analysis.” This work on PDEs is completely independent from the equilibrium results that won Nash…
• ### Which mathematician had the biggest gap between fame and contribution?

22 Mar 2015 | 7:35 pm
(I was going to call this entry  Who was the worst mathematician of all time? but Clyde Kruskal reminded me that its not (say) Goldbach's fault that his conjecture got so well known, in fact its a good thing! I'll come back to Goldbach later.) Would Hawking be as well known if he didn't have ALS?  I suspect that within Physics yes, but I doubt he would have had guest shots on ST:TNG, The Simpsons, Futurama, and The Big Bang Theory (I just checked the IDMB database- they don't mention Futurama but they do say he's a Capricorn. I find that appalling that they mention a Scientists…
• ### Feeling Underappreciated

19 Mar 2015 | 6:58 am
As academics we live and die by our research. While our proofs are either correct or not, the import of our work has a far more subjective feel. One can see where the work is published or how many citations it gets and we often say that we care most about the true intrinsic or extrinsic value of the research. But the measure of success of a research that we truly care most about is how it is viewed within the community. Such measures can have a real value in terms of hiring, tenure, promotion, raises and grants but it goes deeper, filling some internal need to have our research matter to our…
• ### Has anything interesting ever come out of a claimed proof that P=NP or P ≠ NP?

15 Mar 2015 | 7:25 pm
When I was young and foolish and I heard that someone thinks they proven P=NP or P ≠  NP I would think Wow- maybe they did!. Then my adviser, who was on the FOCS committee, gave me a paper that claimed to resolve P vs NP!   to review for FOCS.  It was terrible. I got a became more skeptical. When I was older and perhaps a byte less foolish I would think the following: For P=NP proofs: I am sure it does not proof P=NP BUT maybe there are some nice ideas here that could be used to speed up some known algorithms in practice, or give some insights, or something. Could still…
• ### Quotes with which I disagree

12 Mar 2015 | 4:25 am
Often we hear pithy quotes by famous people but some just don't hold water. "Computer science is no more about computers than astronomy is about telescopes." Usually attributed to Edsger Dijkstra, the quote tries to capture that using computers or even programming is not computer science, which I agree. But computer science is most definitely about the computers, making them connected, smarter, faster, safer, reliable and easier to use. You can get a PhD in computer science with a smarter cache system, you can't get a PhD in Astronomy from developing a better telescope lens. "If your…
• ## IMA Journal of Applied Mathematics - current issue

• ### Examination of SGP4 along-track errors for initially circular orbits

20 Mar 2015 | 8:46 am
This paper examines the SGP4 orbit propagation equations for the specific case of an initially circular satellite orbit, with the aim of understanding the along-trajectory errors that are observed in practice. In particular, the SGP4 equations are compared with analytic expressions obtained by means of a regular perturbation expansion and two discrepancies have been found in the along-track angle u, both of order J2 (the primary earth oblateness term):A slightly different value for the linear trend, governing the secular behaviour, A missing sinusoidal term, with period equal to the orbit…
• ### The existence and uniqueness of short-run equilibrium of the Dixit-Stiglitz-Krugman model in an urban-rural setting

20 Mar 2015 | 8:46 am
The Dixit–Stiglitz–Krugman model is one of the most fundamental models in the new economic geography, and is described by the nominal wage equation. We obtain sufficient conditions for the existence and uniqueness of short-run equilibrium of this model, where a short-run equilibrium is defined by a solution of the nominal wage equation under the condition that the worker distribution is given. We construct an iteration scheme to obtain numerical short-run equilibria. No restriction is imposed on the total number of locations where economic activities are conducted.
• ### Entropy generation for magnetohydrodynamic heat transfer over a non-isothermal stretching sheet with variable viscosity

20 Mar 2015 | 8:46 am
An analysis has been presented to analyse the entropy generation in an electrically conducting fluid under the influence of a constant transfer magnetic field over a linearly stretching non-isothermal flat sheet with suction and blowing at the sheet, in the presence of temperature-dependent viscosity. The governing equations for the problem were changed to dimensionless ordinary differential equations using a similarity transformation. The transformed governing equations in the present study were solved numerically using the Runge–Kutta method with the shooting technique. A comparison…
• ### Mixed convection boundary-layer flow near the lower stagnation point of a horizontal circular cylinder with a second-order wall velocity condition and a constant surface heat flux

20 Mar 2015 | 8:46 am
The mixed convection boundary-layer flow near the lower stagnation point of a horizontal circular cylinder with a second-order slip velocity model and a constant surface heat flux is investigated. By choosing appropriate similarity variables, the partial differential equations and boundary conditions governing the flow are transformed into a similarity system. This is solved numerically for different values of the governing parameters. These solutions can have two branches, an upper and a lower branch, over certain ranges of the mixed convection parameter. These numerical studies are…
• ### A new mode reduction strategy for the generalized Kuramoto-Sivashinsky equation

20 Mar 2015 | 8:46 am
Consider the generalized Kuramoto–Sivashinsky (gKS) equation. It is a model prototype for a wide variety of physical systems, from flame-front propagation, and more general front propagation in reaction–diffusion systems, to interface motion of viscous film flows. Our aim is to develop a systematic and rigorous low-dimensional representation of the gKS equation. For this purpose, we approximate it by a renormalization group equation which is qualitatively characterized by rigorous error bounds. This formulation allows for a new stochastic mode reduction guaranteeing optimality in…

• ## eon

• ### 3.14.15 and Einstein

26 Mar 2015 | 6:42 pm
14 March 2015, was supposed to be the Pi day of the century — for obvious reasons. 14 March is also Einstein’s birthday, and 2015 interestingly marked 100 years of the theory of relativity. I liked this article written by Jeff Edelstein that described how Einstein tutored a 12 year old girl in maths. As Edelstein wrote, this could be a hoax, but personally for me, some stories (or myths) are worth retelling. There are two lovely quotes in the article, both recollections of the girl being tutored. He’d say we’re not going to bother with the homework problem. First he’d give…
• ### Under Promise and Over Deliver

26 Mar 2015 | 6:20 pm
Mr Lee Kuan Yew, the man responsible for making modern Singapore what it is today, passed away on 23 March 2015, aged 91. Incidentally it was also Emmy Noether’s birthday. I have wanted to start off my class by showing the google doodle but the lesson plan had to change in view of the more sombre and relevant news. The mathematical exploits and Emmy and Sophie will have to wait for another day. Throughout this whole week of national mourning, much have been wrote about his sagely advice. In particular, the current minister of defence said that Mr Lee often reminded the younger ministers…
• ### Kobon Triangles

2 Feb 2015 | 7:44 pm
Students occasionally have great ideas. Was discussing a problem that originated from some students but was not very well posed. We managed to reformulate it as the maximum number of triangles that can be formed with n lines. This turns out to be well known and already discussed by Gardner who stated that the problem came from Kobon Fujimura. A link to a MAA column by Ed Pegg Jr as well as the OEIS entry. The problem is incidentally still not completely solved.
• ### Translate

22 Jan 2015 | 8:59 pm
It’s slightly old but I only recently saw this article about how Google Translate make use of linear transformation. The new book on my desk eta products and theta series identities has the following quote in the preface. In der Theorie der Thetafunctionen ist es leicht, eine beliebig grosse Menge von Relationen aufzustellen, aber die Schwierigkeit beginnt da, wo es sich darum handelt, aus diesem Labyrinth von Formeln einen Ausweg zu finden. Die Besch¨aftigung mit jenen Formelmassen scheint auf die mathematische Phantasie eine verdorrende Wirkung auszu¨uben – G. Frobenius, 1893…

7 Aug 2014 | 8:19 pm
I was trying to solve an olympiad type problem involving a nested radical of the form $$\sqrt{a+b\sqrt{r}}.$$ I had managed to discover that $$\sqrt{a^2- b^2r}$$ is an integer but it turned out the trick is to rewrite $$\sqrt{a+b\sqrt{r}} = c + d\sqrt{r}.$$ Of course, one naturally asks if this is a specific incident or is there a general theory. This lead to digging up an article that I painstakingly photocopied from the library from back when photocopying was the norm. The article in question is by Susan Landau from 1994 in the Math. Intelligencer titled “How…
• ## WordPress Tag: Mathematics

• ### Erratum...

24 Mar 2015 | 12:50 am
For me, studying math seems to gently bring back old memories… I remember smells and situations I never had thought about… Simple acts like picking up groceries at a store in London come to my mind. Or hearing a friend’s dad sing in church. Details from those times but somehow helping me to put myself back into my own skin… As if I’d been mis-remembering how that era really felt. Turns out I was wrong… Dead wrong in my last post. I said that, as long as a particular vector field was dependent only on the particular point you’re looking at, then the…
• ### Scary Stuff; a Potential Nasty Surprise

23 Mar 2015 | 9:32 pm
If it were to come true, Wally Broecker would earn yet another, deserved scientific accolade: The Great Ocean Conveyor. More from WHOI here. “The climate system is an angry beast and we are poking it with sticks,” said Dr. Wallace S. Broecker of Columbia University’s Lamont-Doherty Earth Observatory, who was one of the first to raise the alarm about abrupt climate change. ”We don’t know whether it’s going to pay attention to the pokes. But if it does, it might rise up and do something we don’t like.” (Courtesy of the New York Times.) Update. 2015-03-24, 20:44 EDT More on this…
• ### Emmy Noether, mathematical genius

23 Mar 2015 | 8:24 pm
Emmy Noether’s Google Doodle Emmy Noether was no less than “The most significant creative mathematical genius thus far produced since higher education of women began.” according to Einstein. The reason you’ve probably never heard of her is the profound sexism that was rampant in the late 19th and early 20th centuries. Though she was prevented, as a woman, from enrolling in university classes, she obtained permission from her professors to audit. After graduation she taught at the Mathematical Institute of the same university (Erlangen) without pay for seven years.
• ### Google Doodle on Emmy Noether

23 Mar 2015 | 7:01 pm
Today’s Google Doodle (the stylized version of the google logo on the google homepage) honors Emmy Noether, the mathematician behind Noether’s Theorem. Noether’s theorem is incredibly important to modern physics because it explicitly works out the relationship between continuous symmetries of nature and conserved quantities. Thus, invariance with respect to time translation requires conservation of energy, spatial translation invariance leads to conservation of momentum, rotational invariance leads to conservation of angular momentum, U(1) symmetry leads to charge…
• ### Previously On Apartment 3-G

23 Mar 2015 | 5:30 pm
First, I wanted to point folks who missed it over to my mathematics blog, since I did another comic strip review over there, and there aren’t really exactly word problems to do except the one that I solve for you. Second, A Labor Of Like tried very, very helpfully to fill in what’s happened in the backstory to Apartment 3-G, since I’ve given up all hope of understanding what’s happening in it, and I didn’t want that to get lost in the comments where nobody sees them. Here’s the attempt at filling in the backstory: Previously on Apartment 3-G: While on her…
• ## Mr. L's Math

• ### Pi Day Pics

10 Mar 2015 | 10:06 am
Here’s a great set of pictures for math teachers and other pi fans, found at NETWORKWORLD.  This year Pi Day is special, because it happens on 3/14/15, and the decimal representation of pi is 3.1415 . . . Some folks are calling it Pi Day of the Century – we’ll see.
• ### Spiral Crosses – a Rotation and Dilation Exercise

29 Dec 2014 | 12:14 pm
This is a great exercise for Common Core Geometry instruction in the area of transformations. HINT: highlight a slider’s button, then use your cursor keys for fine adjustment; play around with the numbers to get pleasing shapes. Use slider n for number of iterations Use slider r for rotation in 0.001 increments Use slider d for dilation in 0.001 increments Build command structure in 3 steps: Enter Dilate[poly1, d^i], where i = 1, 2, 3 to find pattern Enter Rotate[Dilate[poly1, d^i], i r π], where i = 1, 2, 3 to find pattern Enter Sequence[Rotate[Dilate[poly1, d^i], i r π], i, 1, n, 1]…
• ### Polygons and Diagonals

29 Dec 2014 | 11:15 am
Number of diagonals in a polygon: If n = number of vertex points, then D = number of diagonals = n(n-3)/2. Slider n controls the number as well as the color. In the Advanced tab, Red = n / 36, Green = 1 – n / 36, and Blue = 0, so the color changes from Green to Red as the number of sides moves from 3 to 36. reference: I modified sonom’s idea from http://tube.geogebra.org/material/show/id/137056 The downloadable file can be found here. My other GeoGebraTube apps can be found here
• ### Spirograph-Epitrochoid Earth and Moon

29 Dec 2014 | 10:47 am
An epitrochoid is the path traced by a point on a circle (M) that travels on the outside of another circle (E). This can be used to model the path of the Moon (M) in orbit around the Earth (E). There are about 13.3 revolutions(n) of the Moon about the Earth in one year. -credit-Malin Christersson-http://www.geogebratube.org/material/show/id/87141 The downloadable file can be found here. My other GeoGebraTube apps can be found here
• ### Polar Vector Clock

29 Dec 2014 | 10:17 am
Polar definitions: Sec=90°-(6a)°, Min=90°-(a/10)°, Hour=90°-(a/120)° NOTE 1: when using polar coordinates a semicolon is needed NOTE 2: “Alt-o” (letter O, not number 0) gives degree symbol Vectors are used for clock hands. -from wikimedia commons: the clock face background, and set at Layer=0; other graphics are at Layer=1 -Animation speed = 0.00023148 to move second hand accurately -credit: Malin Christersson-http://www.malinc.se/math/geogebra/slideren.php The downloadable file can be found here. My other GeoGebraTube apps can be found here

• ## Institute for Mathematics and Computer Science

• ### Three Tips for Nurturing the Good Habit of Delayed Gratification

12 Mar 2015 | 6:50 am
The ability to delay gratification has been shown in various studies to be a strong predictor of academic success, even more so than IQ. Can parents help nurture this ability in children? Yes! But it takes more than a didactic approach. Many parents are probably familiar with the famous marshmallow experiment where young children were given a choice between one marshmallow now or two if they could wait 15 minutes. It’s helpful to recall that the original experiment focused not on whether the children could wait but rather on what strategies helped them to wait. Rochester University…
• ### Not Your Father’s Algebra: A New Online Course for Talented Students

11 Feb 2015 | 10:00 pm
EMF teaches modern algebra, which has important applications in public-key cryptography. The Institute for Mathematics and Computer Science (IMACS) recently released its first online algebra course, Algebra: Groups, Rings and Fields. This is the tenth course in the Elements of Mathematics: Foundations (EMF) program for talented secondary school students. Our latest self-paced offering has generated a fair amount of inquiries from parents seeking options for their mathematically advanced child. The answers to some of those questions can be found in the FAQ at elementsofmathematics.com. IMACS…
• ### Which Computer Programming Language Should My Child Learn?

14 Jan 2015 | 10:00 pm
The "learn to code" movement has emphasized teaching computer programming to children, and so many parents are asking, "Which language should my child learn?" It’s easy to be overwhelmed by the myriad choices: Java, Python, Ruby, C++, Objective-C, and so on. Ten years ago, the list of languages would have been different, but the question would still have been the same. So instead of focusing on learning a particular language that is popular at the moment and wondering if it’s the "right" choice, consider that your child would benefit most from…
• ### Improving Math Education through History

17 Dec 2014 | 10:00 pm
A recent study published in the Philosophy of Mathematics Education Journal confirms that teachers’ images of mathematics and their mathematics history knowledge are interlinked. According to the study’s lead author, Danielle Goodwin of the Institute for Mathematics and Computer Science (IMACS), "By and large, the teachers with low history scores in this study were the teachers who exhibited narrow, negative views of mathematics." Key findings from the study include: Respondents with low history scores were more likely to indicate that they believed mathematics overall…
• ### IMACS Student Shiva Oswal Named MOEMS Regional Mathlete of the Year

19 Nov 2014 | 10:00 pm
IMACS student Shiva Oswal is ready for his soccer match. This month’s IMACS Blog features Shiva Oswal, one of the top performers in our Elements of Mathematics: Foundations (EMF) self-paced, online program for talented secondary school students. Shiva has been enrolled in EMF since the beginning when IMACS introduced the first course of the series in late 2012. As his mom told us, “[O]ur son is an avid user of online educational resources. I recently asked him to pick his favorite online course. He answered, ‘most definitely EMF, by a wide margin’.” Please tell…
• ## mathrecreation

• ### are you experienced?

25 Mar 2015 | 7:52 pm
Don't despairA search for "math" in the iTunes store is likely to disappoint (maybe "maths" or "mathematics" would provide better results). I haven't tried Math Drills Lite - it is likely the last thing I would want to download, yet it comes up first.A sad situationBut this is happy post, because there is a math app, well, more of an interactive book, that is engaging, interesting, well written, and attractively designed, that conveys mathematics as its practitioners and enthusiasts see it: beautiful and creative, not dry and confusing. Mathema, written by two…
• ### a tile arrangement, or airport fun

19 Mar 2015 | 7:57 pm
Is there anything nicer than a notebook with grid-lined pages? Maybe, but they are pretty nice - and I count myself very fortunate to have just obtained a new one. And thanks mostly to a longish wait in the Vancouver airport, this is what ended up on page one.The image on the tiles are the simplest non-trivial knot, the trefoil, which you could also put together using these other tiles.Along a given row or column (following the slight skew), the tiles are alternately rotated back and forth by 90 degrees - in the rows they alternate between being placed at 0 and 90 degrees or at 270 and…
• ### season's greetings

11 Mar 2015 | 7:39 pm
• ### bus number factoring

27 Jan 2015 | 7:09 pm
Each bus in Ottawa has a four digit number that identifies it (like 4476 above). One thing to do while riding, if you don't have a bus transfer to play with, is to pass the time factoring that bus identifier (it's also printed on the inside of the bus, in case you miss it getting in).We all know some basic divisibility rules to help with factoring: If it ends in a zero, it's divisible by 10, if it's even then its divisible by 2, if it ends in a 5 then it's divisible by 5. You may know that if the last two digits of a number are divisible by 4 then the whole number is also divisible by 4…
• ### Some notes on the Kaprekar function

2 Dec 2014 | 5:50 pm
Consider a 3 digit number, say 395. Take its digits and form the greatest and least possible 3 digit numbers and subtract them: 935 - 359 = 594. Now do the same with the result:  954 - 459 = 495. Try it again, and you see that the process has hit a fixed point: 954 - 459 = 495.The Kaprekar function involves taking a number, computing two shuffles of its digits (the shuffle with the greatest value, and the one with the least value), and then taking the difference of those two shuffles. So for an integer n, if g is the number you get from re-arranging the digits of n from greatest to…
• ## Math-Blog

• ### Measuring Up, SAT Scores, and Coding Interviews

16 Mar 2015 | 6:00 am
Introduction Measuring Up: What Educational Testing Really Tells Us is a 2008 book by Professor Daniel Koretz of Harvard. Koretz, the Henry Lee Shattuck Professor of Education at Harvard, is a noted expert on educational assessment and testing policy. Professor Koretz is both an excellent writer and also public speaker as evidenced by many short videos at BigThink and YouTube. Measuring Up is an “accessible” book that tries and mostly succeeds in teaching the basic concepts, both statistical and testing specific, of educational achievement tests such as the SAT (the test formerly…
• ### Review of Damned Lies and Statistics: Untangling Numbers from the Media, Politicians, and Activists

9 Mar 2015 | 6:00 am
DAMNED LIES AND STATISTICS: Untangling Numbers from the Media, Politicians, and Activists (UPDATED EDITION) Joel Best University of California Press Berkeley and Los Angeles, California 2001, 2012 Print Length: 213 pages My Rating: 4/5 Introduction Damned Lies and Statistics is an excellent book on the misuse of statistics by Joel Best, a Professor of Sociology and Criminal Justice at the University of Delaware. Lies was first published in 2001 and updated in 2012. There is also a sequel More Damned Lies and Statistics: How Numbers Confuse Public Issues. Lies gives many examples of bad…
• ### Book Review: e: the Story of a Number

16 Feb 2015 | 6:00 am
e: The Story of a Number by Eli Maor Princeton Science Library Series Published by Princeton University Press, 41 William Street, Princeton, New Jersey 08540 Copyright © 1994 by Princeton University Press Page Count: 248 pages My Rating: 4/5 Introduction e: The Story of a Number is a book about e (2.718281828459045…), sometimes known as Euler’s Number or Euler’s Constant after the great mathematician Leonhard Euler. e: The Story of a Number is an “accessible” math book, rather than a “popular” math book, that tries to teach an advanced topic (really…
• ### Book Review: A Mind for Numbers

26 Jan 2015 | 6:00 am
A Mind for Numbers How to Excel at Math and Science (Even if you Flunked Algebra) by Barbara Oakley, Ph.D. JEREMY P. TARCHER/ PENGUIN Published by the Penguin Group Penguin Group (USA) LLC New York, New York 10014 2014 My Rating: 3/5 Introduction A Mind for Numbers is a good but not great book on techniques for learning math and science. The book covers a large range of methods including alternating between “diffuse” and “focused” thinking, “chunking,” practicing recall to firmly imprint knowledge in long term memory, the “memory palace” method…
• ### Review of Falling Behind? Boom, Bust, and the Global Race for Scientific Talent

12 Jan 2015 | 6:00 am
Falling Behind? Boom, Bust, and the Global Race for Scientific Talent by Michael S. Teitelbaum Princeton University Press March 30, 2014 Introduction Falling Behind? is a recent (March 2014) book by Michael Teitelbaum of the Sloan Foundation, a demographer and long time critic of STEM (Science, Technology, Engineering and Mathematics) shortage claims. Falling Behind? is an excellent book with a wealth of data and information on the history of booms and busts in science and engineering employment since World War II, STEM shortage claims in general, and lobbying for “high-skilled”…

• ## MathFour

• ### Seeing Math at Church

25 Mar 2015 | 3:04 am
This is part of Wordless Wednesday…
• ### Finding Math in the Strangest Places

11 Mar 2015 | 3:21 am
I’ve written a lot. Including 160 posts on my crazy “cutting my teeth” blog, Idearella.com, two dozen guest posts, and 530 posts on MathFour.com. But my favorites pieces all involve how math can be seen in weird and unusual ways. Which prompted me to collect some of my fav’s. Which I thought I’d share, in case you’re as curious about it as I am. pickles toilet paper zombies Christmas trees lipstick potato chips crossing the street bedsheets and folding them tattoos drug dealing laundry hurting the ones you love social media marriage hearts and more…
• ### Gathering and Organizing Your Math Folder

6 Mar 2015 | 2:39 am
I attended the 4.0 Schools “Essentials” class last week in New Orleans for That’s Math. This quote struck me: “Creativity comes from constraint.” It made me itch to do another 50 word post. So I thought I’d combine a couple of my favorite Friday fun flurries – 50 Word Friday AND Five Minute Friday. This week’s prompt for #FMFParty is gather. Take a peek under the obnoxious image to see the short 50 words I have to say about it (that I wrote in under 5 minutes!)… Here goes… Did the Tasmanian Devil organize some of your students’ folders? Try these…

3 Mar 2015 | 2:36 am
Most students use a math book to do their assignments. But rarely do students read a math book. But some people do use math books for other reasons. Like: To look at examples For reference To teach themselves Regardless of why you open a math book, knowing a bit about it can be helpful. Here’re some things to ask about your math book: What’s on the inside front and back covers? Sometimes there are formulas, charts or other handy things there. Also look for a quick reference card near the back that can be torn out. If there’s too much information for the front and back…
• ### Prime Factorization Graphic Organizer

19 Feb 2015 | 3:56 am
I have a thing for prime factorizations. Okay, you could say I’m obsessed. And it kills me when students mess it up because of bad handwriting. They think they’re bad at it when they just need a little help neatening things up. So I created this handy prime factorization graphic organizer (free to download, btw) to help out. Here’s a couple of examples of how to use it. You can have your students use highlighters around the primes (keeping them from obscuring the numbers) or you can have them just trace the boxes. And when your students get into multiplying fractions, they…
• ## CSE Blog - quant, math, computer science puzzles

• ### Dividing Pizza with a Clock

5 Mar 2015 | 9:47 pm
Source: Alok Goyal Puzzle Page ( http://alokgoyal1971.com/ ) . Alok is ex-IIT Delhi, Partner at Helion VC Problem: Part I (Easy): Using a clock, divide a pizza among 12 people Part II (Difficult): Using a clock, divide a pizza among 11 people?
• ### Buying in Rocket Ships and Selling in Fire Sale

18 Feb 2015 | 5:11 am
Source: Asked to me by Ankush Jain (CSE IITB 2011, Morgan Stanley Quant Associate). He took it from Algorithms Design book by Tardos and Kleinberg Problem: Easy case: You’re trying to buy equipments whose costs are appreciating. Item i appreciates at a rate of r_i > 1 per month, starting from \$100, so if you buy it t months from now you will pay 100*((r_i)^t). If you can only buy one item per month, what is the optimal order in which to buy them? Difficult case: You’re trying to sell equipments whose costs are depreciating. Item i depreciates at…
• ### Box in Box problem

23 Jan 2015 | 2:31 am
Source: Sent to me by Sudeep Kamath Problem: Airline check-in baggage has size restriction by ​so-called ​linear dimension: length + breadth + height should not exceed 62 inches. Prove that you can't "cheat" by packing a box with higher linear dimension into a box with ​lower​ linear dimension.
• ### Fibonacci Multiple Puzzle

21 Jan 2015 | 2:30 am
Source: Mailed to me by Kushagra Singhal, Ex-IIT Kanpur, PhD Student at University of Illinois at Urbana-Champaign Problem: Prove that for any positive K and a natural number n, every (n*K)th number in the Fibonacci sequence is a multiple of the Kth number in the Fibonacci sequence. More formally, for any natural number n, let F(n) denote Fibonacci number n. That is, F(0) = 0, F(1) = 1, and F(n+2) = F(n+1) + F(n). Prove that for any positive K and natural n, F(n*K) is a multiple of F(K).
• ### Gold Silver Numbers Puzzle

19 Jan 2015 | 3:00 am
Source: Mailed to me by JDGM ("regular commenter JDGM")Problem:The integers greater than zero are painted such that:• every number is either gold or silver.• both paints are used.• silver number + gold number = silver number• silver number * gold number = gold numberGiven only this information, for each of the following decide whether it is a gold number, a silver number, or could be either:1.) gold number * gold number2.) gold number + gold number3.) silver number * silver number4.) silver number + silver number
• ## Motion Math

• ### Yes! Cool! I did it! Look!

26 Mar 2015 | 11:31 am
We recently participated in the NYC Innovation Zone’s Short Cycle Challenge, piloting the Motion Math Educator in the 4th grade classrooms of teachers Helen Bruno-Raccuia, Jackie Hickman, and Cris Curatolo of P.S. 30 Westerleigh School in Staten Island. Here, Helen describes our collaboration: Thank you Helen, Jackie, Cris, and your students for all your great feedback!
• ### Free Pilot Program for Educators

16 Dec 2014 | 7:04 am
Exciting news: if you give us regular feedback, you can pilot the full Motion Math: Educator game suite and dashboard for free this school year! Sign up here. In September, our team released the Motion Math: Educator, which bundles all of our games into one iPad app and provides a dashboard for teachers to monitor student progress based on gameplay. We are excited to announce that we are now offering free pilots of the Educator at the classroom, school, and district level, in exchange for regular feedback from educators who join the pilot program. To date, we have over 3 million downloads of…
• ### From Entreé to Spice: the Promise of Assessment

3 Nov 2014 | 9:16 pm
(note: this post appeared on the Common Sense Media blog) The rapid ascent of digital technology in education presents a singular opportunity to transform assessment. With the capacity to capture student learning in a variety of ways, and in minute detail, educational technologies can engage students with authentic learning while simultaneously providing teachers with rich, formative data. In this way, assessments can evolve from a separate entreé at the end of the meal to a spice that seamlessly blends into and enhances the main course. Formative data can come from unlikely sources, such…
• ### Games and Learning on the Motion Math: Educator

2 Oct 2014 | 10:19 am
Lee Banville from Gamesandlearning.org interviewed us about the Motion Math: Educator launch with good questions about our reasons for focusing on teachers.
• ### Introducing the Motion Math Educator!

1 Oct 2014 | 3:27 pm
Big news: we’ve just launched the Motion Math Educator, our classroom solution. What is the Educator? First, it’s access to all our delightful iPad elementary games: Fractions, Zoom, Hungry Fish, Wings, Questimate, Match, and Pizza, plus two new games we’ll add this school year. Second, the Educator is the answer to many questions we’ve heard from teachers: “Can I see how my students are doing in your games?” “How does mastery in your games connect to mastery of Common Core standards?” “Can I load in my student roster?” Here’s…

• ## Marauders of the Lost Sciences

• ### Nash on the Bargaining Problem

14 Mar 2015 | 3:15 pm
What follows is John Nash’s treatment of a simple two-person game as to way to model bargaining. UTILITY THEORY OF THE INDIVIDUAL The concept of an “anticipation” is important in this theory. This concept will be explained partly by illustration. … Continue reading →
• ### Weyl on the Gibbs Phenomenon in Fourier Analysis

11 Mar 2015 | 1:36 pm
Weyl describes the early influence the Gibbs Pheonomeon had on his research. Notice how A. A. Michelson, who was an experimental physicist, criticized in Nature mathematicians notions of the convergence of a sequence of functions. Since this is a lecture … Continue reading →