# Mathematics

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.

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. 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.

Here are the rules for 2 through 11... The last digit is divisible by 2. 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.

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. 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. Here is an alphabetical list of online mathematics books, textbooks, monographs, lecture notes, and other mathematics related documents freely available on the web.

I tried to select only the works in book formats, "real" books that are mainly in PDF format, so many well-known html-based mathematics web pages and online tutorials are left out. Click here if you prefer a categorized directory of mathematics books. The list is updated almost on a daily basis, so, if you want to bookmark this page, use the button in the upper right corner. 001. Higher Algebra Jacob Lurie | Harvard University Published in 2011, 950 pages. 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. This page has been split into TWO PARTS.

This, the first, looks at the Fibonacci numbers and why they appear in various "family trees" and patterns of spirals of leaves and seeds. The second page then examines why the golden section is used by nature in some detail, including animations of growing plants. Let's look first at the Rabbit Puzzle that Fibonacci wrote about and then at two adaptations of it to make it more realistic.

This introduces you to the Fibonacci Number series and the simple definition of the whole never-ending series. Fibonacci's Rabbits. 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 above two figures are rearrangements of each other, with the corresponding triangles and polyominoes having the same areas.

Nevertheless, the bottom figure has an area one unit larger than the top figure (as indicated by the grid square containing the dot). The source of this apparent paradox is that the "hypotenuse" of the overall "triangle" is not a straight line, but consists of two broken segments. As a result, the "hypotenuse" of the top figure is slightly bent in, whereas the "hypotenuse" of the bottom figure is slightly bent out. The difference in the areas of these figures is then exactly the "extra" one unit.

The Tesseract. Buddhabrot (LlopSite) NumberSpiral.com - 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.

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. 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:

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. Spell and Summon. This card curiosity is attributed to Lewis Carroll.

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. ALL. I'm afraid we need to use...MATH. Wonders of Math - The Game of Life. What is the Game of Life? By Paul Callahan Rules of the Game of Life Life is played on a grid of square cells--like a chess board but extending infinitely in every direction. A cell can be live or dead. 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.

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 John D. The Thirty Greatest Mathematicians. This is primarily a list of Greatest Mathematicians of the Past, but I use 1930 birth as an arbitrary cutoff, and three of the "Top 100" are still alive as I write.

Click for a discussion of certain omissions. Please send me e-mail if you believe there's a major flaw in my rankings (or an error in any of the biographies). Obviously the relative ranks of, say Fibonacci and Ramanujan, will never satisfy everyone since the reasons for their "greatness" are different. I'm sure I've overlooked great mathematicians who obviously belong on this list. Please e-mail and tell me! Physics Flash Animations.

We have been increasingly using Flash animations for illustrating Physics content. This page provides access to those animations which may be of general interest. The animations will appear in a separate window. The animations are sorted by category, and the file size of each animation is included in the listing.

### Scale/Ratio/Proportions

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. :)