An extensive live of math words with definitions and graphics--all useable (if printed in their entirety) for classrooms. There is also a page to go to a bunch of charts (though these seem most useable for younger grades.)
A website that has gathered and organized thousands of videos (and math ones included). The videos seem to come from other websites, so I suggest ensuring if it is okay to use the video per that site. The site is beginning to organize by Common Core Curriculm as well.
This site is an online calculator that will let you put in points, functions y(x), polar r(theta), or parametric. It will let you download or export your graphs.
Number sense, concepts, and operations word wall
The purpose of the mathematics word wall is to identify words and phrases that students need to understand and use so as to make good progress in mathematics. Mathematical language is crucial to children's development of thinking. If students do not have the vocabulary to talk about math concepts and skills, they cannot make progress in understanding these areas of mathematical knowledge. They need to be familiar with mathematical vocabulary and mathematical terms to understand written and spoken instructions.
See math word wall resources >
Click the link to access some examples of math words for a word wall. They have inspired me to find creative ways to display higher level math vocab such as "line of symmetry" and "slope".
Greg Tang, author and mathematician, has written many children's books about math (check out your local library to see if they have any of his books!), and he has a Master's in Math Education from NYU. His website is full of classroom materials, games, and puzzles for both the math teacher and the math student. Check it out!
A math education blog that contains some great musings on what it means to be a math teacher and how we can improve, including project and lesson ideas!
As an introduction to our unit on surface area and volume of solids, my students investigated cross-sections of solids through a Play-Doh Cross Sections lab activity. Materials: play-doh, paper plates, dental floss, plastic knife, and ruler.
A great math activity idea that revolves around using Play-Doh to help students learn about solid cross-sections. I've always had a hard time visualizing these types of things, and I wish my teachers had used this lesson idea! I can't wait to try it!
This blogger posts her lesson schedule for each of her classes (Algebra 1, Algebra 2, and Pre-Calculus) online and has links to a lot of the cool activities she does in class.