Math on the Web

May 13

Dictionary of Numbers

I will always remember reading the book Cadillac Desert. It was the first book that I read that was vividly able to contextualize really large numbers. Seeing this awesome new chrome extension reminded me of that experience. The Dictonary of Numbers will take any number you find on the internet and do exactly that for you: contextualize it. Check out the video.

I found this extension via my favorite tech tools blog: Free Technology for Teachers

Mar 13

Facebook + Math

Screen shot 2013-03-27 at 12.33.35 PM

The WolframAlpha Facebook app allows you to enjoy “the book” math-style. Network graphs, maps, posting frequencies. It is pretty awesome and a bit geeky. Enjoy.

Feb 13

Graphing Calculator Emulators

ti-83 emulator
I caught a Lifehacker article about a webapp that emulates the most popular graphing calculators. The app is called JsTIfied. I prefer a webapp like Desmos that is built for the web, not meant to emmulate hardware. But if you know the TI-83 inside and out or are nostalgic for those good old days, this might be for you.

Feb 13

Math + Rap

This is a great story of a high school math teacher using rap to lift algebra off the page a little. Here is his YouTube channel so you can check out some of the videos mentioned in the NPR story above.

Thanks, Colleen, for sending this my way!

Nov 12

Math Search Engine


Here is a great new search engine for math teachers and math students. It solves the problem-concept gulf that often exists between teachers and students. If a math teacher and a student look at 2x+3=17. The teacher will think, “a linear equation.” The student will think “I have to move the the 3 three over and then divide by 2.” As I have tried to encourage my students to use the web more to learn math, this gulf has been a recurring problem. If a student runs into an equation like 2x+3=17 and tries to use Google to learn how to do it, they more than likely will have a problem figuring out what search terms to input (like ’solving linear equations’). On the other side of things if the student throws 2x+3=17 into WolframAlpha, WA solves it, graphs it, gives them alternate forms for the equation. The results are awesome, but don’t do much to connect the student to the larger class of problems. This is where Symbolab is awesome. You can enter a problem and it will connect you to web resources pertaining to the concept of which the problem is an example. Compare these three searches on 2x+3=17

Google’s Search
WolframAlpha’s Search
Symbolab’s Search

Symbolab’s searches aren’t perfect. I noticed the search for 2x+3=17 was better than 2x+3=5 for whatever reason. However, it’s a great start in the right direction. I hope they continue to improve.

Oct 12

Math + Accounting


One of the hardest things to get students to appreciate is the positional number system. It is one those things that seems so simple and inevitable that everyone takes it for granted. It is hard to imagine what life was like before it and what was made possible because of it. This Planet Money podcast captures this enormity of this transition inside of the story of Luca Pacioli, a mathematician responsible for codifying and disseminating double entry book keeping throughout the world. The whole show is great, but if nothing else, listen to the first five minutes.

Oct 12

TED + Math

I was searching for something else and got sucked in by this provocatively titled TED vid, Why Math Instruction Is Unnecessary. It was a well spent 12 minutes. It basically follows how a middle school math teacher’s answer to the question, When will I ever need this?, has evolved over time.

Sep 12

Math + Cartoons

function world

I love this cartoon, Function World by Grant Snider. I found it on Drawn and have beeb subscribed to Snider’s Incidental Comics blog ever since. Not every comic is mathematical in nature, but most of them look at the world in bemused abstraction. (like a mathematician) This is one of my favorite comics online, second only to the immortal XKCD.

Sep 12


math tv
I’ve been mashing up web resources for my College Algebra class this semester. For the most part, I stick to Khan academy videos because students tend to like them and the library is so extensive. On some topics, I’ve been pushed out onto the web to supplement. One of the best math video resources I’ve found on the web is MathTV. There are a couple of things I really like about it. One, videos are introduced by the problem not by the topic. I have noticed, when pushing my students to find web resources on their own, a huge block for them is coming up with the relevant search terms for the skill e.g. simplifying complex fractions. However, they are much better at recognizing when a problem is similar to the one they want to solve. Therefore, MathTV makes it easier/faster for them to find what they are looking for. The second reason I like MathTV is they have multiple explanations of the same problem by different tutors. Sometimes there is even a Spanish language option.

math video demo

The frustrating thing is that I can’t link directly to a list of videos on a particular skill. You can see them altogether, but there isn’t a unique URL for that view. They have a playlist creation function on the website that didn’t work very well that is supposed to accomplish this. But even if it did, that is a lot more work than I want to do. It would be nice to copy the link for “absolute value equations” directly from my browser, and then paste it into my discussion system.

Aug 12

Math + Mind Tickle

I place $20 in a box.
So do you.
Now the box contains $40, and we both know it.
I sell the box to you for $30.
And we both walk away with a $10 profit.

Jay sent over a link this great problem. It’s from one of my favorite blogs Futility Closet. This is the perfect kind of problem to throw out in class…easy to remember and easy to think through in a few minutes. What’s lovely is that initially it seems so plausible and yet impossible that they both profit $10. It reminds me of a Nova show (embedded below) I was watching on neuroscientists studying magic. Most tricks rely on our visual system’s strong bias toward detecting and anticipating motion. I feel like this problem and ones like it trick our reason, possibly with the momentum of language? Whoa, that got deep! Better stop right there.

Watch Magic and the Brain on PBS. See more from NOVA scienceNOW.