I love this series of dynamic sketches on exterior angles from @dynamic_math. It's the visual nature that I like the most and the fact that you really get the idea of the fact that the sum is 360 (regardless of the polygon). I have done something similar here using Geometer's Sketchpad (I should turn it into a websketch) but I think I like the way this works better.
Curriculum Tags: MPM1D, MFM1P https://www.geogebra.org/m/mKzJCf5p

I can't decide whether I like this or not. In some ways it reminds me of the old MathBlaster type games where the math was embedded in a game that already existed but as I played this Tetris game with embedded factoring, I just wanted to play more. Maybe that's because I used to love Tetris. Thanks to @ddmeyer for pointing this one out.
Curriculum Tags: Gr7, Gr8 http://mei.org.uk/factris

The idea that when you have student centred learning leads to pushback from students is not new. In my opinion a lot of that comes from students who find it easier to just be told what to do. I don't think they are actually learning better in that traditional setting but students like it because it is so passive. When you have student centred learning, they actually have to work. None the less, I like this sketchnote from @Wheeler_Laura on the topic. Follow the link for more details.
Curriculum Tags: All https://mslwheeler.wordpress.com/2017/07/19/pushback-to-student-centred-learning-sketchnote/

I'm a sucker for anything about primes. Here's a new @Numberphile video talking about the distance between large primes. I was particularly interested in the algorithm for showing the distance using factorial notation. But the crazy logarithmic expression in the proof is something that should turn any grade 12 student's head
Curriculum Tags: MHF4U https://www.youtube.com/watch?v=BH1GMGDYndo

I have liked @Desmos' Polygraph from the get go. So it seems odd that it has taken so long for someone to take it offline. In this case it is @Mr_Stadel who has come up with a nice hack to do them online. And all it requires is some plastic sleeves and whiteboard markers. He's done Lines and Parabolas so far. Why not add your own?
Curriculum Tags: MPM1D, MFM1P, MPM2D, MFM2P, MBF3C, MCF3M, MCR3U http://mr-stadel.blogspot.ca/2017/06/low-tech-polygraph.html

More tips from @Mr_Stadel on using Polygraphs in class. This time it's using the idea of a word bank to help students (and a list of "taboo" words that students cannot use). The idea is to help students use more academic language while using Polygraphs.
Curriculum Tags: MPM1D, MFM1P, MPM2D, MFM2P, MBF3C, MCF3M, MCR3U http://mr-stadel.blogspot.ca/2017/07/polygraph-word-bank.html

And Finally from @Mr_Stadel's quest to maximize the use of Polygraph, he introduces the idea of a PolyGraph "Word Jar". Watch the video below and then follow the link for more info on how to use it.
Curriculum Tags: All http://mr-stadel.blogspot.ca/2017/07/polygraph-vocab-jar.html

It's more than just making things fun or exciting for kids in math. Students need to be emotionally engaged in what is going on. I feel like that is true for just about any subject but here are some ideas to help that process. Thanks to @KMarkPet for pointing this one out.
Curriculum Tags: All https://ww2.kqed.org/mindshift/2016/08/02/how-to-make-math-more-emotionally-engaging-for-students/

Here's a nice quick video to deal with proportional reasoning (via bar graphs) from Dane Elhert. Click on the link below to have the answer revealed.
Curriculum Tags: Gr7, Gr8 https://whenmathhappens.com/2017/06/22/bar-graph/

I'm a sucker for posts about assessment. So when @MrOrr_Geek posted this story about assessment, I was in. I love the premiss because it's about changing the paradigm about assessment in his classes. And not to give it all away but I loved the tag line at the end "Assessment is power not punishment". That is, most kids fear assessment but he is trying to build a culture in his classes where assessment empowers students. Even if you don't use @Freshgrade, the underlying principles are pretty intriguing. Watch below to find out how.
Curriculum Tags: All http://mrorr-isageek.com/conalls-assessment-story/

I have been sitting on this activity for a while. I actually made it last December but just got around to posting it now. We have started to develop a number of activities using a continuum model for student practice where the practice problems become incrementally more difficult as students progress (at their own pace). In this case we've tackled trig identities. Take a look.
Curriculum Tags: MCR3U http://engaging-math.blogspot.ca/2017/06/trig-identities-continuum.html

I like card matching activities because they get students to do the math but in a way that is much more palatable for students. In this case @marybourassa (adapted from @pamjwilson) has students match up different representations of linear functions (points, slope, equations, graphs) and students have to match them. We did a similar activity with functions in context here but this one is good for analytic linear functions.
Curriculum Tags: MPM1D, MFM2P http://marybourassa.blogspot.ca/2017/06/linear-matching.html

There is no shortage of questions you can ask about the Tim Horton's Roll Up the Rim contest. This time @mathletepearce has turned it into a 3Act Task on Probability.
Curriculum Tags: Gr7, Gr8, MBF3C, MDM4U https://tapintoteenminds.com/3act-math/roll-up-the-rim-150/

Some evidence as to why you can't just look at the summary statistics for data sets without looking at the visual representations. In the spirit of the Anscomb's Quartet (my post here), here is a number of data sets that have the same summary but different graphs. Don't miss the Datasaurus too.
Curriculum Tags: MDM4U https://www.autodeskresearch.com/publications/samestats

This is a fight we have all the time. That is, the notion that students come into your class thinking that they are not a "math person" or the societal idea that it's even OK to claim you are not a math person (yet they would never say "I don't read"). Thanks to @michelecooper for this one.
Curriculum Tags: All https://www.thespec.com/news-story/7389739-the-math-problem-i-m-not-a-math-person-/

Sometimes examples of math are right under our noses. In this case, it's an example of a dilatation that is seen every time the Twitter app opens. Get the video or animated gif at the folder below.
Curriculum Tags: Gr7, Gr8 https://drive.google.com/drive/folders/0B9algQOOR_bkMmZBXzV4ZmtmZnc

I love showing this video to students to remind them that we are all doing complex math all the time. That is, every time we catch a ball, our brain is doing complex mathematics to figure out where to put our hands to catch it. In this clip, Willy Mays see's the ball hit and immediately turns around and sprints to where he thinks the ball will land. The problem that most students have is putting those calculations on paper.

As @ddmeyer points out, this XKCD image has been out for a while and he has suggested it be used for introducing the topic of the coordinate plane before but now he and his crew have Desmosified it into a really fun and dynamic way to introduce the concepts of the coordinate plane (or even help fill the gaps in for those who still struggle with graphing points). The premiss is pretty simple: given various fruits, decide where it fits on a linear tasty/untasty scale and a perpendicular linear Easy/Difficult (to eat) scale.
Curriculum Tags: Gr7, Gr8 http://blog.mrmeyer.com/2017/pomegraphit-how-desmos-designs-activities/

Here's a nice twist on a standard concept from @dpscher. We've all seen 10x10 multiplication grids before (both static and dynamic) where students have to look for multiples of what ever number. But now that 10x10 grid itself is dynamic. That is, it's dimensions. So you can have your kids explore how the patterns change as the grid changes. This may seem really elementary but students who have good number sense will have an easier time when performing other math tasks. So students at any grade can practice with this to hone their skills.
Curriculum Tags: All http://www.sineofthetimes.org/exploring-multiples-on-a-dynamic-number-grid/

I love this lesson from @Wheeler_Laura where she takes advantage of her student winning Gold at OFSAA in the 1500m championship (pretty fast - almost cracked 4min in grade 9). She turns that into a 3Act task where she has her students wonder how much of a head start they would need so if they were walking and he was running, they would end up at the finish line at the same time. And like any good 3Act task there is a great reveal. In this case, she has her students actually do the experiment. Check out the link for the entire lesson.
Curriculum Tags: MPM1D, MFM2P https://mslwheeler.wordpress.com/2017/06/10/running-vs-walking-headstart-mpm1d-mfm2p-3actmath/

I remember a time (more than 15 years ago) when I was just getting into the groove of having students investigate mathematics as a matter of habit when one student asked "sir, when are you going to teach us". Heavy sigh. None the less, I am always happy when others share thoughts on this same mater. In this case from @K8Nowak with the title "So When do I teach?" where that is being asked by a teacher.
Curriculum Tags: All http://function-of-time.blogspot.ca/2017/06/faq-so-when-do-i-teach.html

I totally love this new video and activity from @MrOrr_Geek. Just watch the video below and tell me you are not right in there ready to solve. Of course there is a whole lesson that goes along with this so make sure you go to the link below to get it all.
Curriculum Tags: MPM1D, MFM1P http://mrorr-isageek.com/polygon-pile-up/