# Math

• ## Most Topular Stories

• ### In Praise of Proofs by Contradiction that Aren't

Scientific American - Math
28 Aug 2014 | 5:00 am
If you don't know what to do, do something. That's one of my mottos when I teach math (and it's probably good life advice too). Last year, I taught introductory analysis (basically calculus with the... -- Read more on ScientificAmerican.com
• ### 3D Tic Tac Toe Puzzle

CSE Blog - quant, math, computer science puzzles
10 Jul 2014 | 12:19 pm
Source: Shared by Alok Mittal (Cannan Partners) Problem: A 3x3 tic tac toe has 8 "winning lines" (3 horizontal, 3 vertical and 2 diagonals). How many "winning lines" does the 3x3x3 3D tictactoe have? There is a brute force solution, and then there is the aha! solution.
• ### Fraction Game: My Closest Neighbor

Let's Play Math!
6 Aug 2014 | 11:30 am
[Feature photo above by Jim Larrison, and antique playing cards below by Marcee Duggar, via Flickr (CC BY 2.0).] I missed out on the adventures at Twitter Math Camp, but I’m having a great time working through the blog posts about it. I prefer it this way — slow reading is more my speed. Chris at A Sea of Math posted a wonderful game based on one of the TMC workshops. Here is my variation. Math concepts: comparing fractions, equivalent fractions, benchmark numbers, strategic thinking. Players: two to four. Equipment: two players need one deck of math cards, three or four players…
• ### Homepage

Search for "math OR mathematics"
30 Aug 2014 | 12:40 am
Cheney Mayor Tom Trulove presented the key to the city to ESPN commentator and Eastern Washington University alumnus Colin Cowherd during last Saturday's "Tailgating Begins Here" rally... At its Aug. 25 study session, the Airway Heights City Council addressed some noise and yard concerns in the city.
• ### Spot light on tailor-made multicyclic type of polymers

Mathematics News -- ScienceDaily
27 Aug 2014 | 6:37 pm
Scientists have synthesized multicyclic type of polymers for the first time offering insights for tailoring polymer properties as well as the mathematics of complex geometries.
• ## Search for "math OR mathematics"

• ### Homepage

30 Aug 2014 | 12:40 am
Cheney Mayor Tom Trulove presented the key to the city to ESPN commentator and Eastern Washington University alumnus Colin Cowherd during last Saturday's "Tailgating Begins Here" rally... At its Aug. 25 study session, the Airway Heights City Council addressed some noise and yard concerns in the city.
• ### AZ 'Get Into Energy' Consortium Launches Cybersecurity Degree...

30 Aug 2014 | 12:26 am
Avondale, AZ August 30, 2014 The demand is increasing for highly trained technicians to protect against and minimize threats to cybersecurity.
• ### Immigrants enter job market through Pa. casinos

30 Aug 2014 | 12:21 am
The gambling industry in Western Pennsylvania is betting on refugee immigrants. And casinos say it's paying off.
• ### Lessons in winning

30 Aug 2014 | 12:21 am
If the Seahawks are going to repeat as Super Bowl champions - something that hasn't been done in a decade - they're going to do so because they go into every day not thinking about repeating as Super Bowl champions.
• ### Judge slaps cable's Marty

30 Aug 2014 | 12:15 am
Green, 57, was convicted Friday of trespassing following a provincial court trial in which he acted as his own lawyer.

• ## Mathematics News -- ScienceDaily

• ### Spot light on tailor-made multicyclic type of polymers

27 Aug 2014 | 6:37 pm
Scientists have synthesized multicyclic type of polymers for the first time offering insights for tailoring polymer properties as well as the mathematics of complex geometries.
• ### Flu outbreak provides rare study material

26 Aug 2014 | 6:10 am
Five years ago this month, one of the first U.S. outbreaks of the H1N1 virus swept through the Washington State University campus, striking some 2,000 people. A university math and biology professor has used a trove of data gathered at the time to gain insight into how only a few infected people could launch the virus's rapid spread across the university community.
• ### Combining math and music to open new possibilities

25 Aug 2014 | 3:53 pm
The power of mathematics to open new possibilities in music has been demonstrated by scientists for years. Modern experiments with computer music are just the most recent example.
• ### Learning by watching, toddlers show intuitive understanding of probability

25 Aug 2014 | 9:33 am
Most people know children learn many skills simply by watching people around them. Without explicit instructions youngsters know to do things like press a button to operate the television and twist a knob to open a door. Now researchers have taken this further, finding that children as young as age 2 intuitively use mathematical concepts such as probability to help make sense of the world around them.
• ### Neuroscience and big data: How to find simplicity in the brain

24 Aug 2014 | 12:23 pm
Scientists can now monitor and record the activity of hundreds of neurons concurrently in the brain, and ongoing technology developments promise to increase this number. However, simply recording the neural activity does not automatically lead to a clearer understanding of how the brain works. In a new article, researchers describe the scientific motivations for studying the activity of many neurons together, along with a class of machine learning algorithms for interpreting the activity.
• ## Scientific American - Math

• ### In Praise of Proofs by Contradiction that Aren't

28 Aug 2014 | 5:00 am
If you don't know what to do, do something. That's one of my mottos when I teach math (and it's probably good life advice too). Last year, I taught introductory analysis (basically calculus with the... -- Read more on ScientificAmerican.com
• ### Readers Respond to "A Crisis In Physics?"

23 Aug 2014 | 8:15 am
Letters to the editor from the May 2014 issue of Scientific American -- Read more on ScientificAmerican.com
• ### What Is the Goal of a Math History Class?

22 Aug 2014 | 5:30 am
I'll be teaching a math history class for the first time this semester. I'm excited to be teaching it, but I've noticed that preparing for this class has been very different from preparing for other... -- Read more on ScientificAmerican.com
• ### Science Media Beset with Gender Gaps

21 Aug 2014 | 12:52 pm
In the fall of 2005, I and a couple hundred other new students at Columbia University's journalism school walked into a lecture hall for a series of welcome speeches, and two things happened that... -- Read more on ScientificAmerican.com
• ### Physics Week in Review: August 16, 2014

16 Aug 2014 | 2:21 am
This week on Virtually Speaking Science, I chatted with astrophysicist Katie Freese, author of a new book, The Cosmic Cocktail: Three Parts Dark Matter. -- Read more on ScientificAmerican.com

• ## NYT > Mathematics

• ### From a Compound in the Brazilian Hills, Excellence in Math Emerges

27 Aug 2014 | 9:00 pm
The National Institute for Pure and Applied Mathematics in Rio is gaining attention as a hidden gem in a country with few world-renowned educational institutions.
• ### Top Math Prize Has Its First Female Winner

12 Aug 2014 | 9:00 pm
A professor at Stanford who made an important discovery about dynamical systems joined three other mathematicians in accepting the Fields Medal.
• ### How Math Got Its ‘Nobel’

9 Aug 2014 | 9:00 pm
The true story behind the field’s most prestigious award.
• ### ‘Too Much Fun’ in Learning

4 Aug 2014 | 9:00 pm
A reader writes that “our children have too much fun, and not enough teaching.”
• ### Americans Are Bad at Math, but It’s Not Too Late to Fix

3 Aug 2014 | 9:00 pm
Americans rank in the bottom five in numeracy, and some believe gambling is a good deal. But there are ways for people to improve their knowledge of math.
• ## Loren on the Art of MATLAB

• ### Age is No Barrier to Exploring Ideas and Concepts in MATLAB and Simulink

25 Aug 2014 | 11:24 am
Age is No Barrier to Exploring Ideas and Concepts in MATLAB and SimulinkI’d like to introduce you to this week’s guest blogger, Graham Dudgeon. Graham is with our Industry Marketing Team at MathWorks, and focuses on the Utilities & Energy Industry. In this blog, Graham shares a story about age being no barrier to exploring ideas and concepts in MATLAB and Simulink.Hi Everyone, and thank you Loren for inviting me to be a guest blogger. This story begins with my dog, waiting patiently at the patio door expecting either of my two sons to let her in. She was out of luck. I am no…
• ### Ever Needed to Move a Figure?

11 Aug 2014 | 8:53 am
Have you ever needed to move a figure? Perhaps because it is offscreen>? Or at least the menus or close box are not visible? This happens to me from time to time when I get code from someone else who is programming specifically to the size of their display. Working on a laptop, I often have fewer available pixels. What to do?ContentsHow to Find my Figure?Degrees of FreedomHave You Needed Help Locating Something?How to Find my Figure?I used the Function Browser to search for "move figure" and found movegui. It might be just the ticket for you.Degrees of FreedomAs you can see from the…
• ### Write Once, Deploy Anywhere

28 Jul 2014 | 8:03 am
Guest blogger Peter Webb returns with another in an occasional series of postings about application deployment.ContentsDeployment TargetsDeploying to MATLABDeploying to the DesktopDeploying to a Java ApplicationReuse, Don't RewriteDeployment TargetsI've written a MATLAB application that reports on the presence of contaminants in surface water, using a publically available database of water quality observations maintained by the United States Geological Survey and the Environmental Protection Agency. Many groups of people might be interested in this kind of information. MATLAB made it easy to…
• ### Analyzing Fitness Data from Wearable Devices in MATLAB

14 Jul 2014 | 5:18 am
Collecting and tracking health and fitness data with wearable devices is about to go mainstream as the smartphone giants like Apple, Google and Samsung jump into the fray. But if you collect data, what's the point if you don't analyze it?Today's guest blogger, Toshi Takeuchi, would like to share an analysis of a weight lifting dataset he found in a public repository.ContentsMotivation, dataset, and prediction accuracyData preprocessing and exploratory analysisPredictive Modeling with Random ForestPlot misclassification errors by number of treesVariable ImportanceEvaluate trade-off with ROC…

30 Jun 2014 | 10:22 am
I have been posting blogs about MATLAB with code examples for many years. Steve Eddins, my fellow blogger of Steve on Image Processing fame, developed and maintains an internal tool that automates a lot of tasks and I rely on it to publish my blog posts.One of my guest bloggers, Toshi Takeuchi, showed me a new tool he found, and he would like to do a quick introduction.ContentsWhy publish to a blog?InstallationEnable Remote PublishingCredentialsAdd a plot to your MATLAB fileAdd a link to a file for DownloadLink to another post on your blogAdd a tooltipAdd notes and warningsAdd categories and…

• ## Homeschool Math Blog

• ### Math Mammoth Grade 7-A is here!

29 Aug 2014 | 2:46 pm
I know it's Labor Day weekend, but... Math Mammoth Grade 7-A is here! Please note: Only part 7-A is available for now (as of August 2014). Part B is expected to be ready sometime in early 2015.Math Mammoth Grade 7-A is the first half of the pre-algebra curriculum from Math Mammoth. Part A worktext deals with:introduction to basic algebra conceptsintegers and their operationssolving one-step equations, including with negative numbersoperations with negative rational numberssolving linear equations and writing equations for word problemsgraphing linear equations and an introduction to the…
• ### Story of Maryam Mirzakhani

21 Aug 2014 | 12:01 pm
I think some of you will enjoy reading the story of Maryam Mirzakhani, an iranian Mathematician, and a woman, who just recently won the most prestigious award in the world of mathematics: the Fields Medal. She is the first woman to win a Fields Medal!
• ### Math Mammoth August sale!

17 Aug 2014 | 11:20 am
>Sale at Kagi!Get ALL downloads and CDs at Kagi store at 25%, 30% or even 35% off!Use coupon code MAMMOTH25 at Kagi store. Get 25% off when your order total is less than $50.Get 30% off when your order total is at least$50 but less than $80.Get 35% off when your order total is at least$80!The sale lasts till September 2, 2014. You will find links to order pages at Kagi all around MathMammoth.com site — they are located under each book's cover image. Or use these direct links to the order pages at Kagi:Order Light Blue seriesOrder Blue seriesOrder Golden and Green SeriesOrder Make It…
• ### SALE on Math Mammoth printed books!

7 Aug 2014 | 4:09 pm
Rainbow Resource is running a 20% off sale on the printed versions of Math Mammoth books! This offer runs till August 25, 2014.
• ### Fun & artistic fractions tool

6 Aug 2014 | 2:13 pm
Here's an online fractions activity that is somewhat artistic and that some of you might find fun.Unitize fractions on a gridConceptua Fractions is offering this tool for free during this summer. Here's a screenshot:First, you drag a red rectangle or a triangle that is going to be your UNIT. It corresponds to 1.Then, you make rectangles and triangles of the other colors. Your task is then to figure out their area compared to the UNIT you established in the beginning, and type it in as a fraction or a mixed number. For example, in the picture below, my UNIT is actually 4 squares. The blue…
• ## Let's Play Math!

• ### Quotable: I Do Hate Sums

29 Aug 2014 | 10:51 am
I’ve been looking for quotes to put at the beginning of each chapter in my math games books. I found a delightful one by Mrs. LaTouche on the Mathematical Quotations Server, but when I looked up the original source, it was even better: I am nearly driven wild with the Dorcas accounts, and by Mrs. Wakefield’s orders they are to be done now. I do hate sums. There is no greater mistake than to call arithmetic an exact science. There are Permutations and Aberrations discernible to minds entirely noble like mine; subtle variations which ordinary accountants fail to discover; hidden…
• ### Math Teachers at Play # 77 via Math = Love

26 Aug 2014 | 3:10 pm
Math Teachers at Play is a traveling collection of math tidbits — games, lesson ideas, and more — from around the Internet. It moves around from month to month, and the August edition is now posted at Math = Love blog. What a fun list of math posts to browse! Math Teachers At Play: Blog Carnival Edition # 77 Welcome to the 77th edition of the Math Teachers at Play Blog Carnival! I’m super excited to be hosting this carnival because I’ve been reading it for years! Yes, I am that crazy person who started reading math teacher blogs as a high school junior. I think you are…
• ### Do You Blog About Math?

18 Aug 2014 | 2:00 pm
by Mike Licht, NotionsCapital.com It’s carnival time again. Activities, games, lessons, hands-on fun — if you’ve written a blog post about math, we’d love to have you join our Math Teachers at Play (MTaP) math education blog carnival. Posts must be relevant to students or teachers of school-level mathematics (that is, anything from preschool up through first-year calculus). Old posts are welcome, as long as they haven’t been published in past editions of this carnival. Click here to submit your blog post. Browse all the past editions of the Math Teachers at Play blog…
• ### Fractions: 1/5 = 1/10 = 1/80 = 1?

13 Aug 2014 | 5:23 am
[Feature photo is a screen shot from the video "the sausages sharing episode," see below.] How in the world can 1/5 be the same as 1/10? Or 1/80 be the same as one whole thing? Such nonsense! No, not nonsense. This is real-world common sense from a couple of boys faced with a problem just inside the edge of their ability — a problem that stretches them, but that they successfully solve, with a bit of gentle help on vocabulary. Here’s the problem: How can you divide eight sausages evenly among five people? Think for a moment about how you (or your child) might solve this puzzle,…
• ### Fraction Game: My Closest Neighbor

6 Aug 2014 | 11:30 am
[Feature photo above by Jim Larrison, and antique playing cards below by Marcee Duggar, via Flickr (CC BY 2.0).] I missed out on the adventures at Twitter Math Camp, but I’m having a great time working through the blog posts about it. I prefer it this way — slow reading is more my speed. Chris at A Sea of Math posted a wonderful game based on one of the TMC workshops. Here is my variation. Math concepts: comparing fractions, equivalent fractions, benchmark numbers, strategic thinking. Players: two to four. Equipment: two players need one deck of math cards, three or four players…
• ## Basic mathematics blog

• ### Counting money worksheets

25 Aug 2014 | 12:46 pm
• ### Counting worksheets

25 Aug 2014 | 11:28 am
• ### Common mistakes in math

19 Aug 2014 | 2:30 pm
Some common mistakes in math and how to avoid them when doing your math problems
• ### Volume of irregular shapes

28 Jul 2014 | 1:28 pm
Learn to calculate the volume of irregular shapes using commonly used volume formulas
• ### Geometry word problems

28 Jul 2014 | 5:40 am
A collection of geometry word problems to help you practice a wide variety of concepts in geometry. All problems come with the solution

• ## ChapterZero

• ### Julia, once more

9 Aug 2014 | 12:43 pm
Julia + PyCall + CCall + Gadfly or PyPlot (+ Julia Studio ?) looks delicious. The only feature that absolutely needs to be added is shared memory parallelism (why wasn’t this an initial core feature of the language?), but I’m extremely excited by the current awesomeness of the Julia ecosystem. I recommend you get into it now, if you’re a scientific computation person. Update: Julia has experimental support for shared-memory arrays on Unix, which is really all that I need at this point. Great!
• ### a bit on word embeddings

25 Jul 2014 | 9:31 pm
Lately I’ve been working almost exclusively on continuous word representations, with the goal of finding vectorial representations of words which expose semantic and/or syntactic relationships between words. As is typical for any interesting machine learning problem, there are a glut of clever models based on various assumptions (sparsity, hierarchical sparsity, low-rankedness, etc.) that yield respectable embeddings. Arguably, however, the most well known of these representations are the word2vec models due to Mikolov et al., which are part of a larger class of neural network-based…
• ### Installing Hadoop on Ubuntu (works for Ubuntu 12.04 and Hadoop 2.4.1)

18 Jul 2014 | 4:11 pm
I’m trying to use LDA on a large amount of data. A quick recap: Tried vowpal wabbit … it’s fast, I’ll give it that, but it’s also useless: the output is dubious (what I think are the topics look like they haven’t changed very much from the prior) *and* I have no idea how it maps onto topics and documents (the documentation is AWFUL, and the dimensions of the output files are WONKY). Tried two implementations of SCVB0, a stochastic collapsed variational bayes LDA algorithm: one doesn’t work at all (as in, it stalls on any amount of data — so…
• ### Sharing numpy arrays between processes using multiprocessing and ctypes

1 May 2014 | 4:32 pm
Because of its global interpreter lock, Python doesn’t support multithreading. To me, this is a ridiculous limitation that should be gotten rid of post-haste: a programming language is not modern unless it support multithreading. Python supports multiprocessing, but the straightforward manner of using multiprocessing requires you to pass data between processes using pickling/unpickling rather than sharing memory. Needless to say, this slows down execution when large amounts of data need to be shared by processes. In my case, I’ve been using multiprocessing to speed up the training…
• ### Eigenvector two-condition number for a product of PSD matrices

7 Apr 2014 | 9:31 am
I’m pushing to submit a preprint on the Nystrom method that has been knocking around for the longest time. I find myself running into problems centering around expressions of the type $$B^{-1}A$$, where $$A, B$$ are SPSD matrices satisfying $$B \preceq A$$. This expression will be familiar to numerical linear algebraists: there $$B$$ would be a preconditioner for a linear system $$A x = b,$$ and the relevant quantity of interest is the spectral radius of $$B^{-1} A$$. It’s not hard to show that the spectral radius of this product is at most 1… but instead, I’m…
• ## Computational Complexity

• ### Sixteen Years in the Making

28 Aug 2014 | 4:23 pm
Every paper has a story but Sunny Daniel's Arxiv paper from yesterday deserves a blog post. We begin in 1982 when Ravi Kannan proved that Σ2 (the problems computable in NP with an NP oracle) cannot have n2 size circuits. Kannan's result hold for nk-size circuits but for this story we'll keep it simple. Kannan had an ingeniously simple proof. By diagonalization you can create a language L in Σ4 that does not have n2-size circuits. Now there are two cases: SAT doesn't have n2-size circuits. Since SAT is in Σ2 we are done. SAT has n2-size circuits. Then by Karp-Lipton Σ4 = Σ2 so L…
• ### A Deadly Side of Complexity

25 Aug 2014 | 4:50 pm
Better algorithms can lead to better medicine and save lives. Just today Tim Gowers discusses Emmanuel Candès' ICM Plenary Lecture, which among other things describes how Candès' work on compressed sensing leads to shorter MRI scans for children, greatly reducing the risk of oxygen deprivation. Prove P = NP with a practical algorithm, and you'll conquer that worst of our diseases. Sounds great until you realize what we can't do. I was talking to a cancer researcher recently and he points out that many of their challenges are indeed algorithmic. But he also brings up the contrapositive.
• ### Turing's Oracle

21 Aug 2014 | 6:38 am
My daughter had a summer project to read and summarize some popular science articles. Having heard me talk about Alan Turing more than a few times, she picked a cover story from a recent New Scientist. The cover copy says "Turing's Oracle: Will the universe let us build the ultimate thinking machine" sounds like an AI story but in fact more of an attack on the Church-Turing thesis. The story is behind a paywall but here is an excerpt: He called it the "oracle". But in his PhD thesis of 1938, Alan Turing specified no further what shape it might take...Turing has shown with his universal…
• ### Complexity versus Algorithms: The FOCS Challenge

18 Aug 2014 | 2:15 pm
In recent years, I've heard complaints from my complexity colleagues that FOCS and STOC are mostly algorithms and from the algorithm buddies that STOC and FOCS are mostly complexity. What exactly counts as a complexity or algorithms paper has become quite blurred in recent years. So let's try an experiment. Below is a poll I've created using titles from the upcoming FOCS conference. Which of these papers do you consider complexity? Does complexity in the title make them a complexity paper?  If you are interested, you can find the manuscripts for most of these papers on the FOCS accepted…
• ### Favorite Theorems: Limited Independence

14 Aug 2014 | 2:02 pm
When can limited randomness act as well as true random bits? Polylogarithmic independence fools AC0 circuits by Mark Braverman (JACM 2010) To explain this result consider choosing uniformly from among the following four strings: 000 110 101 011 If we look at any two of the bits, say the first and third, all four possibilities 00 10 11 01 occur. The sequence is thus 2-wise independent. We can get 2-wise independence using only two random bits to choose one of the four strings. In general one can get k-wise independent in n-bit strings using O(k2 log n) random bits. Braverman shows that any…
• ## eon

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…
• ### Millenium Bookball

19 Jul 2014 | 9:54 pm
is a pretty cool mathematical sculpture by George Hart. Gone with the Wind, Charlie and the Chocolate Factory, The Cat in the Hat, Green Eggs and Ham. What is not to like? Speaking of which, I still cannot believe that it was only because of my son who is now four that I read Dr Seuss for the first time in my life. Growing up with parents who do not speak English, I only started reading English books in Primary School. I still remember the joy when I did well in school examinations and the prize was to go to the school hall and select one free book for keeps.
• ### On practice

19 Jul 2014 | 9:56 am
I’m sure I am interpreting this in a context different from Vygotsky who was quoting Lenin Man’s practice, repeated a billion times anchors the figure of logic in his consciousness.
• ### Math videos

9 Jul 2014 | 1:08 am
“Speaker, I’d like to talk about twin prime numbers …” goes McNerney in the US Congress. This took place on 11 Feb 2014. More details may be found here. There is still hope in politics afterall. I would love to see the day when mathematics is discussed in our parliament. I’ve longed known about the discussion on the Monty Hall problem in the movie 21. But it was preceded by a short take on Newton’s or Newton-Raphson method. See the clip here at Mathematics in Movies site.
• ### Prime Mystery

30 Jun 2014 | 3:27 pm
A nice puzzle from Aziz Inan on plus.maths.org The number N represents the first 6 digits of a special number. N consists of three prime numbers put side by side. These three prime numbers come xth, yth and zth on the list of primes, where x, y and z are themselves three consecutive primes (for example, x, y and z could be 3, 5 and 7, in which case we’d be looking at the third, fifth and seventh prime numbers). In addition, if N is split in the middle into two separate numbers, the prime factors of the left part of N add up to its right part. What is N? And what is the special numbers…

• ## WordPress Tag: Mathematics

• ### seq: Count up, count down

26 Aug 2014 | 1:00 pm
A quick note before we get into seq today: If you left a comment in the past 18 hours or so but don’t see it by now, it might have gotten lost in a spam avalanche. Someone out there in the world must have turned up the dial on the spam machine, because I had more than 120 spam comments between noon today and early yesterday evening. For reference, I usually see 10 or 12 in a day. Usually WordPress.com — in spite of all my complaints — does a decent job of filtering out the winners from the losers, but sometimes people get lost in the fracas. If for some reason your comment…
• ### Gambling solved by numbers.

26 Aug 2014 | 10:59 am
• ### Is logic and mathematics part of science?

26 Aug 2014 | 9:38 am
Partial view of the Mandelbrot set. (Photo credit: Wikipedia) Last week was scientism week at Scientia Salon, and I reblogged a post by Coel Hellier on a defense of scientism, mostly by arguing that mathematics was actually part of science.  As I indicated in my comment on that reblog, while I agree with Coel that both logic and mathematics have foundations that are empirically observable (my wording here is actually pretty careful; for why, see this post), I’m not really on board with calling mathematics a science. To some degree, I see this as a bit of semantic issue.  Whether or…
• ### What is Math in Focus?

26 Aug 2014 | 8:45 am
The core of our math curriculum this year is Math in Focus.  What is Singapore Math? Singapore Math is math curriculum developed in the country of Singapore and now used in many schools and districts across the U.S. The math content in Singapore Math is the same as the math content here in America. The difference lies behind the philosophy of pedagogical methods. Singapore Math believes that in first grade, students should be introduced to mathematical concepts to have a strong foundation. It does not mean easy or simple. Singapore Math recognizes what first graders learn in lower school is…
• ### Everyday Math Lessson 1.6

26 Aug 2014 | 8:32 am
Students watched these videos yesterday as they learned about prime and composite numbers. https://learnzillion.com/lessons/786-determine-if-a-number-is-prime-or-composite-using-area-models
• ## Mr. L's Math

• ### Area of Triangle Transformation – Common Core Meets GeoGebra

29 Aug 2014 | 9:48 pm
A triangle can be transformed easily into a rectangle, and the area of the triangle can be found to be half its (base)x(height). One of the strengths of the Common Core curriculum in the area of Geometry is in transformations (translations, rotations, and reflections). A simple rotation is used here to show the area of a triangle. The downloadable GeoGebra file can be found here.   My other GeoGebraTube apps can be found here.
• ### Math and Teaching Quotations for Common Core – Part MP1

29 Aug 2014 | 10:58 am
Math & Teaching Quotations has continued to be one of the most popular pages on my site, and it’s appropriate to revisit this as school resumes across the U.S. Here’s the direct link to quotes on Mr. L’s site. A good quote can go a long way towards brightening my day as well as give students some brain food as they work through their daily tasks. Since the 8 Common Core Practices talk about “big ideas” and overarching goals, quotes fill this niche by allowing the discussion of wider goals – kind of like looking at the forest as opposed to looking at…
• ### MathArt – Pattern of Arcs

29 Aug 2014 | 10:09 am
Here’s a piece of math art based on Jerzy Mil’s work. I’m still deciphering his code that makes this art. One of the nice features of geogebratube is that you can download GeoGebra apps and look at code that others have written to gain new knowledge (math tricks) to create designs and math curricula. For more of Jerzy’s artistic mathematics work, here’s his geogebratube site:  Here’s the link for the app below made from Jerzy’s fine work.
• ### KenKen – Common Core Number Sense Activity

28 Aug 2014 | 1:14 pm
Jackie Murawska, Ed.D., of North Central College - Naperville, Illinois gave a presentation at the Illinois Council of Teachers of Mathematics Annual Meeting October 18, 2013 and I’ve shared some of her slide content below. The link to her entire presentation is below; take a look – she has some nice stuff! Why Is KenKen Good? Fun! I mean – engaging; Builds confidence; Encourages positive attitudes; Aligns with Common Core Standards for Mathematical Practice K-12 Content Here are the Standards for Mathematical Practice for reference: Mathematically proficient students:…
• ### Free Teaching Tool – KenKen Classroom

27 Aug 2014 | 7:02 am
One of the best things I ever did for my students was to teach them how to do KenKen puzzles. They learned problem solving, focus, persistence, number sense, and achieved that “feel good” satisfaction when completing a puzzle. I subscribed to a weekly email from the makers of KenKen that gave our class a set of puzzles to work on; my students always looked forward to the challenge! Here’s the info for this year’s puzzles: On Friday, August 29, a whole new year of the KenKen Classroom Program will begin, bringing you exciting new KenKen puzzles and brainteasers you can…
• ## MathNotations

• ### Explore Inscribed Square in Rt Triangle - CCSS Activity

29 Aug 2014 | 8:39 am
Want Free Answer/Solution/Extension sent to your inbox?Just request this via Blogger Contact Form.Incude(a) Your full name(b) A link to your website/blog if you have one(c) State & Name of school district in which you are teaching (or a student)(d) Grade Level(s) or Math subjects currently teaching or indicate grade level/current math courses if a student. Also indicate if you're teaching LD/Reg/Honors/AP Levels(e) Preferred math problem types (E.g/, Middle School, CCSS, Algebra, Geometry, SAT, Precalculus, Explorations, etc)(f) Indicate if you already subscribe to my blog feed (&…
• ### A Crazy Ages Problem - Is there a place for this in CCSS

28 Aug 2014 | 3:48 am
A variation on a classic for your algebra group! J is as old as K was when J was half the age he'll be in 10 years. If K is y yrs old, express J's current age in terms of y. Want answer and detailed solution sent to your inbox? By now you should know what you have to do. Join the other teachers who have figured it out... Reflections... So you're probably thinking this question is either too hard or irrelevant in the Common Core. I beg to differ! Before having students attempt to solve this algebraically I would encourage my students to experiment with numerical values. For example…
• ### f(x)=(25--x^2)(16-x^2) Algebra 2 CCSS Challenge

26 Aug 2014 | 8:44 am
f(x)=(25--x^2)(16-x^2) P=product of x-int, Q=y-int of graph of f |P| - |Q| =? Generalize! Want free ans/soln sent to your inbox? Just go to http://mathnotations.blogspot.com/2014/08/free-ccsssatchallenge-math.html VISIT ME DAILY ON TWITTER AT twitter.com/dmarain
• ### Back to School Challenge SAT/CCSS Problem

26 Aug 2014 | 6:35 am
Posted on Twitter this morning... (100+99+98+...+51)-(1+2+3+...+50)=? NO calculator/Noformulas! Mental math - 30 seconds! Are you getting your FREE answers and detailed solutions with strategies sent to your inbox?  For details go to http://mathnotations.blogspot.com/2014/08/free-ccsssatchallenge-math.html PLS SHARE THIS WITH COLLEAGUES! Think there's a catch here because there's no such thing as free? Why not ask the teachers who have been receiving these? VISIT ME DAILY ON TWITTER AT twitter.com/dmarain
• ### Free CCSS/SAT/Challenge Math Problems/Solns sent to your inbox?

24 Aug 2014 | 7:51 am
I'm considering a trial run depending on response. Many of these will be similar to the hundreds of Twitter Problems I've posted but more developed and with Answers/Solutions. I will update my progress with this venture and let my readers here and on Twitter know if I will continue. Since it's free at this juncture, I request that you (1) Follow me on Twitter @dmarain (2) Send me request via Blogger Contact Form with the following info: (a) Your full name (b) A link to your website/blog if you have one (c) State & Name of school district in which you are teaching (or a…

• ## MathFour

• ### How Much Weight Does Wet Hair Add?

21 Aug 2014 | 3:47 am
Have you heard that saying, “She weighs 115 pounds, soaking wet”? That saying hit me this morning while stepping out of the shower. I’m doing Weight Watchers and so I’m a bit hyper-focused on weight right now. So I thought I’d do an experiment. With math of course. Do I weigh more soaking wet? I weighed myself before I dried my hair. And then I weighed again, after it was dry. I didn’t do anything else – no consuming or, ahem, evacuating. I kept the same state of clothing. I didn’t move too much for fear I’d lose weight through energy.
• ### All About the Benjamin – How Math Saves Lives

15 Aug 2014 | 8:51 am
This is the story of how a 67% tip on a sushi bill saved a teenager’s life. Okay, that’s a bit of a hyperbole. But roll with me for a bit. The Back Story This summer I started teaching at a small school for kids with neurological differences 2.5 miles from my house. This was the perfect distance to start run commuting – running to work to get back into my old pre-kid running shape. During inservice for the fall, I attended a two day class on Reasoning Mind’s RMCity with a new colleague, Stephanie. Turns out Stephanie is pretty cool and she’s a runner. A twice…
• ### Even and Odd Numbers – Basic, but Not Easy to Learn

2 Aug 2014 | 3:32 am
You know about even and odd numbers, right? I was visiting with my sister yesterday and she was excited that her 8 year old son had finally grasped the idea. “I know, it’s a pretty basic concept, “ she told me, “but I’m just so excited he finally got it.” Which made me consider it. Are the concepts of even and odd basic? Basic but Not Easy Okay, yes. Even and odd numbers are considered a basic concept. Everyone over the age of 15 or so should have a general idea of which numbers are even and which numbers are odd. But even-ness and odd-ness are NOT easy concepts. Think about it:…
• ### The New Way of Subtracting – Crushing a Facebook Meme

29 Jul 2014 | 1:48 pm
“Oh – I see what they’re doing,” I thought to myself after spending 20 seconds looking at the latest bash-the-common-core meme: The “new way” is really the old fashioned way of giving change, before we had cash registers with computers in them. Getting change, the old fashioned way. I buy something and it costs $12. So I give you$32. (Because I’m a freak OR I anticipate not having so many \$1′s in my pocket after this is over.) Your fancy-schmancy cash register computer is out (or doesn’t exist), so you need to give me change out of your…
• ### “The 12 Touchstones of Good Teaching” is Not So Good

29 May 2014 | 2:44 pm
I just found a list on Pinterest called “The 12 Touchstones of Good Teaching” based on the book of the same title. Of course I had to read it. And of course, I was incensed. One third of the list is good. One third is okay. And one third is deplorable. And all of it is centered on the wrong person. The Good Parts Apparently the list is broken up into three sections: Be Demanding Be Supportive Be Intentional The “Be Supportive” section is the good part. (Note: I’m discussing these out of order.) Item 5 – I engage student interest with every lesson. Item 6 – I interact…
• ## CSE Blog - quant, math, computer science puzzles

• ### "Flawless Harmony" Puzzle

26 Aug 2014 | 2:40 am
Source: AUSTMS Puzzle Corner 35 Problem: Call a nine-digit number flawless if it has all the digits from 1 to 9 in some order. An unordered pair of flawless numbers is called harmonious if they sum to 987654321. Note that (a, b) and (b, a) are considered to be the same unordered pair.Without resorting to an exhaustive search, prove that the number of harmonious pairs is odd.
• ### Minimum sum of numbers in an array

10 Aug 2014 | 10:21 pm
Source: Asked to me on quora ( cseblog.quora.com ) Problem: Given an array of n positive numbers (n ~ 100000), what is the algorithmic approach to find the minimum possible sum (>=0) by using all the numbers in an array? Example 1: 1 2 2 3 4 Answer : 0 (-1+2-2-3+4) Example 2: 2 3 4 7 13 Answer: 1 (+2-3-4-7+13)
• ### Caterer's Problem

5 Aug 2014 | 10:07 pm
Source: Puzzle Toad CMU Problem: You are organizing a conference, with a festive dinner on the first day. The catering service has 1024 different dinner choices they know how to make, out of which you need to choose 10 to be in the dinner menu (each participant will choose one of these during the dinner). You send an email to the 6875 participants of the conference, with the list of all 1024 choices, asking them to rank the choices in linear order from their favorite to their unfavorite. You want to find a list L of 10 choices, such that for any dinner choice d not in the list L, if we run a…
• ### 3D Tic Tac Toe Puzzle

10 Jul 2014 | 12:19 pm
Source: Shared by Alok Mittal (Cannan Partners) Problem: A 3x3 tic tac toe has 8 "winning lines" (3 horizontal, 3 vertical and 2 diagonals). How many "winning lines" does the 3x3x3 3D tictactoe have? There is a brute force solution, and then there is the aha! solution.

3 Jul 2014 | 8:16 am
Source: http://nrich.maths.org/ Problem: A mad robot sets off towards the North East on a journey from the point (0,0) in a coordinate system. It travels in stages by moving forward and then rotating on the spot. It follows these pseudo-code instructions: SUB JOURNEY     DISTANCE = 1000     WHILE (DISTANCE > 0.001)         MOVE DISTANCE         STOP         ROTATE(90, DEGREES, CLOCKWISE)         DISTANCE = DISTANCE / 2     END WHILE     EXPLODE END SUB Where does the…
• ## Math for all Grade blog

• ### Aug 28, Math-Questions

28 Aug 2014 | 2:12 am
Math-Questions
• ### Aug 28, Math-properties

28 Aug 2014 | 2:12 am
Math-properties.
• ### Aug 28, Math-Quiz

28 Aug 2014 | 2:12 am
Math-Quiz.
• ### Aug 28, Math-Puzzle

28 Aug 2014 | 2:12 am
Math-Puzzle
• ### Aug 28, Math-problem-solver

28 Aug 2014 | 2:12 am
Math-problem-solver

• ## Puzzle Games - Challenging Puzzles For You

• ### Puzzle #58 : Write down the number, if you are smart enough!

4 Aug 2014 | 3:28 am
Question : Write down the number “twelve thousand twelve hundred twelve”in the comment box as fast as you can! Answer : Click Here
• ### Puzzle #57 : The number whose letters are in alphabetical order.

27 Mar 2014 | 6:22 am
Question : Can you find a number whose English name has its letters in alphabetical order? Answer : Click Here
• ### Puzzle #56 : Find the number.

26 Mar 2014 | 1:00 am
Question : What number gives the same result, when it is added to 3,and when it is multiplied by 3?Answer : Click Here
• ### Puzzle #55 : Find my parking lot number.

25 Mar 2014 | 3:04 am
Question : What is the number of the parking lot, where my car is parked?Hint : It's an observation puzzle. Answer : Click Here
• ### Puzzle #54 : Solve the Anagram

19 Mar 2014 | 12:32 am