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Calculators, Lessons, and Worksheets - StumbleUpon. Math for Artists: Exponents and Radicals. How do you assess a 14-year-old maths genius? Blog : Test Your “Subitizing” Ability. Recently I found myself reading about “subitizing”, which is the process of instinctively counting small sets of items in a fraction of second.

Blog : Test Your “Subitizing” Ability

For example, try quickly counting a few of these: The Wikipedia article indicates that you can nearly always correctly count four or fewer items in a small fraction of a second. Above four, you start to make mistakes. I wanted to test this claim in Mathematica (using myself as the test subject). I decided to create a simple game in which small groups of items are momentarily displayed on the screen, after which players estimate how many they saw. If you have the free Computable Document Format (CDF) browser plugin (or Mathematica 8) installed, then you can play the game right here in your web browser (if you don’t have the plugin, you’ll just see a placeholder image): The game keeps track of your successes and failures and plots them as a function of how many items were present and the time you were given to count them. Results. Math Playground - Online Math Games that Give Your Brain a Workout.

National STEM Centre - Browse Collection. Nerd Paradise : Divisibility Rules for Arbitrary Divisors. It's rather obvious when a number is divisible by 2 or 5, and some of you probably know how to tell if a number is divisible by 3, but it is possible to figure out the division 'rule' for any number.

Nerd Paradise : Divisibility Rules for Arbitrary Divisors

Here are the rules for 2 through 11... Calculus Video Tutorials. Nature by numbers. The theory behind this movie. We can find interactive sites on the internet (like this) to draw points, move them, and check how the structure becomes updated in real time.

Nature by numbers. The theory behind this movie

In fact, if we have a series of random dots scattered in the plane, the best way of finding the correct Voronoi Telesación for this set is using the Delaunay triangulation. And in fact, this is precisely the idea shown on the animation: first the Delaunay Triangulation and then, subsequently, the Voronoi Tessellation. But to draw a correct Delaunay Triangulation is necessary to meet the so-called “Delaunay Condition”. This means that: a network of triangles could be considered Delaunay Triangulation if all circumcircles of all triangles of the network are “empty”. Notice that actually, given a certain number of points in the plane there is no single way to draw triangles, there are many. You see that in the graph below, extracted from Wikipedia: Podéis verlo en la siguiente gráfica, extraída de la Wikipedia:

Touch Trigonometry. Math is not linear by Alison Blank on Prezi. Playing to Learn Math? by Maria Andersen on Prezi. Khan Academy. Free Mathematics Books. Rader's NUMBERNUT.COM. Conrad Wolfram: Teaching kids real math with computers. PatrickJMT. Alpha—Computational Knowledge Engine. Wolfram Demonstrations Project. Decimal Division. The Dot and the Line : A Romance in Lower Mathematics - une vidéo Cinéma. Golden Ratio. Nature by Numbers. The Fibonacci Numbers and Golden section in Nature - 1.

StumbleVideo - A Night Of Numbers - Go Forth And Multiply. StumbleVideo - A Magic Number - Sixty Symbols. Fractice Mandelbrot deep zoom to 2^316 (bigger than the universe!) Fractal Mandelbrot 2^316. Triangle Dissection Paradox. The Tesseract. Buddhabrot (LlopSite) - Home. Making Math Fun Download Page. Math Gems. Math That Makes You Go Wow. Blog : The Incredible Convenience of Mathematica Image Processing. It’s been possible since Version 6 of Mathematica to embed images directly into lines of code, allowing such stupid code tricks as expanding a polynomial of plots.

Blog : The Incredible Convenience of Mathematica Image Processing

But is this really good for anything? As with many extremely nifty technologies, this feature of Mathematica had to wait a while before the killer app for it was discovered. And that killer app is image processing. Mathematica 7 adds a suite of image processing functions from trivial to highly sophisticated. To apply them to images, you don’t need to use any form of import command or file name references. Is that too much contrast?

OK, but you could just do that in Photoshop, right? Here’s a clown fish, and a command that breaks it into 40-pixel squares. By the way, we’re seeing another neat thing about the integration of images with Mathematica‘s typeset input/output system. And here they are sorted by average pixel value (roughly by brightness): Remember how we made a Manipulate to play with the contrast of an image? Roots. Typesetting math: 8% John Baez December 15, 2011 Around 2006, my friend Dan Christensen created a fascinating picture of all the roots of all polynomials of degree ≤ 5 with integer coefficients ranging from -4 to 4: Click on the picture for bigger view.


PencilWise. PENCILWISE - Equation Analysis Test Take this "test" as your personal challenge.


This test does not measure your intelligence, your fluency with words, and certainly not your mathematical ability. It will, however, give you some gauge of your mental flexibility and creativity. Spell and Summon. This card curiosity is attributed to Lewis Carroll.

Spell and Summon

Lay down eight cards with these values: Now add the values in each column, find a card of that value in the deck, and place it on top of the lower card. Aces count as 1, jacks as 11, queens as 12, and kings as 13. Thus in the first column 1 + 2 = 3, so you’d place a 3 on top of the 2. When you’ve done all four columns, repeat the process, placing a 4 on the 3, etc. Turn the deck face down again and deal 13 cards in a circle, making note of which was dealt first.

Each pile should now contain four cards. ALL. I'm afraid we need to use...MATH. Wonders of Math - The Game of Life. The Socratic Method. The Socratic Method:Teaching by Asking Instead of by Tellingby Rick Garlikov The following is a transcript of a teaching experiment, using the Socratic method, with a regular third grade class in a suburban elementary school.

The Socratic Method

I present my perspective and views on the session, and on the Socratic method as a teaching tool, following the transcript. The class was conducted on a Friday afternoon beginning at 1:30, late in May, with about two weeks left in the school year. This time was purposely chosen as one of the most difficult times to entice and hold these children's concentration about a somewhat complex intellectual matter. A Visual Tutorial in Formal Logic - The 16 Combinations of Meaning. Einstein for Everyone. Einstein for Everyone Nullarbor Press 2007revisions 2008, 2010, 2011, 2012, 2013 Copyright 2007, 2008, 2010, 2011, 2012, 2013 John D.

Einstein for Everyone

The Thirty Greatest Mathematicians. Physics Flash Animations. We have been increasingly using Flash animations for illustrating Physics content.

Physics Flash Animations

This page provides access to those animations which may be of general interest.


  1. virttree Oct 9 2011
    Your pearltree is like the best math collection I've ever seen; The way those 45 pearls take over my screen is spooky in a good way. In my spare time I'll be back to explore this. :)