Dec 14

Did you know?

Here is a fun fact to demonstrate to your students:

Think of two positive integers.
Add them to get a third number.
Add the second number and the third number to get a fourth number.
Continue in this way until you have 10 numbers.
The sum of the 10 numbers is 11 times the seventh number.

found via Futility Closet

Oct 14



I’m really excited about the potential of a new app called MathChat. It is an app that allows students to key in problems, start to solve them, and when they get stuck have their peers comment and help. It is kind of a mobile version of the OpenStudy website. A couple of perks: as students work through expressions/equations, MathChat checks their work line by line. It only tells them if it is equivalent or not. The student still has to find the mistake and fix it. Also, MathChat uses the touch capabilities of the mobile environment, so that peers can give you help by writing on your problem. This is a real nice touch. It is early and I haven’t really had a chance to test drive this app with students, but the app holds a lot of promise.

found via Free Tech for Teachers

Sep 14

Desmos + Math

I was really blown away with Desmos. They just keep getting better. I found out this week they have apps now for i0S and Android and let you upload pictures. I was trying to figure out the parabola of my smile here. I uploaded my headshot and used a slider to play with the leading coefficient. Looks like I’m y=0.4x^2

Aug 14


I got to demo a great new product last week. It is called Mathspace. It is both a web and mobile app, and the real innovation is their exercises allow you to write and check intermediate steps. And their handwriting interpreter is the best I’ve seen. It is a little hard to explain exactly what I mean. Check out the gif above.
There are other perks like adaptive learning, videos, badging, and a gradebook, but it is the above feature that really sets the app apart. The company is young and adding content. Definitely something to watch out for.

Aug 14

Pascal’s Triangle

I caught a great visualization for Pascal’s triangle on Visualizing Math’s Tumblr.

Aug 14

General Solutions to Polynomial Equations

Whenever I’m teaching the quadratic formula I love telling students that there is a formula “like the quadratic” for cubic and quartic equations, but that after that there isn’t any. They seem amazed by it. I guess because it is still amazing to me. I found a real nice graphic by the mathematical poet with each of the formulas. I’m going to pull this out next time I have that discussion so they can see what the formulas look like.

Jul 14

Great Mistakes

I caught a cute feature about Einstein on NPR. It is a quick 4 minute listen. It should make you feel better the next time you make a sign mistake to know that you are in great company.

Jul 14

Math + Myth

I caught an interesting article in Quartz about aspects of American culture that make it a challenging culture in which to learn math. I definitely don’t agree with all their conclusions, particularly about requiring algebra for all, but I agree with the basic observation: the problem of math education has almost nothing to do with the intelligence students.

May 14

The tides of the the quadratic formula

quadratic search

I’m teaching the quadratic formula right now in my classes and just ran across this on my Tumblr. This is the number of google queries for the quadratic formula over time. As Charmed as Charmander says, “It repeats in the same pattern every year. Down in summer, up in September, down again in December and up again in spring time before going down again in the summer.” It makes sense that there is a pattern. It amazes me just how regular it is.

Feb 14

Function Fun

function carnival

Function Carnival is the coolest site I’ve ever seen to develop graphing intuition among students. If you are a math teacher, doing the walk through at the top of the page is a must. It is so clever. This is the second thing Desmos has released in the last 6 months that has blown my mind. Check out this other post on modeling.