I love this activity from @Desmos for introducing probability concepts. Especially the 36 spinner slides. So much goes into coding those pages so having someone do that for you is a gift. Have your kids try it out.
Curriculum Tags: Gr7, Gr8, MBF3C, MDM4U https://teacher.desmos.com/activitybuilder/custom/59233c9aefd17610dbbd684e

I like this activity from @MathEqualsLove about continuous vs discrete data. Students are given six cards with three one of three representations on it (situation, graph and variables). The other two are blank. Great for discussion on the ideas of continuous vs discrete data.
Curriculum Tags: Gr8, MDM4U, MAP4C https://mathequalslove.blogspot.ca/2017/12/introducing-discrete-vs-continuous-in.html

I really like the nature of randomness and as it turns out getting things to be truly random is pretty hard. This tech company that protects 10% of the websites on the net does so by requiring a regular stream of random numbers. And how do they do it? Lava lamps. Thanks to @Esping_Math for this one.
Curriculum Tags: Gr7, Gr8, MBF3C, MDM4U https://nerdist.com/wall-of-lava-lamps-protect-internet-traffic/

Do you want to know how much garland you need for your conical shaped Christmas tree? How about how to win that Christmas match of Monopoly with your family? Listen to @FryRsquared on @SciFri as she talks about her (and @Mathistopheles ) new book "The Indisputable Existence of Santa Claus (The mathematics of Christmas)". Listen here
Curriculum Tags: All https://www.sciencefriday.com/segments/how-can-math-make-your-holidays-merrier/

We put a new activity on our blog that combines some of the work of @JoBoaler and @FawnpNguyen. Using visual patterns we made these 32 visual pattern cards to give to kids to talk about how the pattern grows. Then they develop the general term and finally I think that when you have all of the different terms you can start to develop some ideas on how to get those general terms more easily.
Curriculum Tags: Gr7, Gr8 http://engaging-math.blogspot.ca/2017/12/visual-pattern-cards.html

@MrOrr_Geek has added a new feature to his @MathBeforeBed site. Just enter your email and you will get 20 pages each with two different prompts for your students to show their thinking. The Math Before Bed has great starters for kids of all ages. So check that out too.
Curriculum Tags: Gr7, Gr8 http://mathbeforebed.com/share-your-thinking-printouts/

I like activities that involve students communicating mathematically to each other. In this activity from @MaryBourassa she has her grade 12 students pairing up. One person picks a graph and has to describe it to their partner. Their partner has to draw it. Get the downloads at the link.
Curriculum Tags: MHF4U, MCV4U http://marybourassa.blogspot.ca/2017/12/rate-of-change-graphs.html

I love this video from @standupmaths for spreading precise Christmas mathematical cheer. These are instructions (and a rant) on how to make a scientifically and mathematically accurate snowflake. There is actually a lot of math here from six fold symmetry to trig and radian measure.
Curriculum Tags: Gr7, Gr8, MPM1D, MFM1P, MPM2D, MFM2P, MHF4U https://www.youtube.com/watch?v=BIiEsIDenTk

A new site from the Ministry of Ontario's @mathconnects is Math Path Ontario. This site has many videos and other resources connecting Ontario math courses with careers. You (or your students) can either choose their course pathway and it will show careers that it will lead to or they can choose the career and it will show the proper course pathway. Plus once you click on the career, you will get a video connecting it to math.
Curriculum Tags: All http://www.mathpathontario.ca/

A new resource from @mathletepearce called mathisvisual.com combines some concepts in number sense starting with counting and currently ending with adding and subtracting integers. And all done visually. I am sure there will be more to come but take a look at what is there so far.
Curriculum Tags: Gr7, Gr8, MAT1L, MAT2L http://mathisvisual.com/

Thanks to @MSBJacobs for pointing out this site. It's for Chalk Dust Magazine which is "A Magazine for the Mathematically Curious". Many great articles and puzzles. And if you are quick you can enter the current Christmas based puzzle for a chance to win a copy of The Indisputable Existence of Santa Claus by Hannah Fry and Thomas Oléron Evans
Curriculum Tags: All http://chalkdustmagazine.com/

If you are dealing with metric prefixes or imperial metric conversions then this episode might be useful. It starts with the story of losing a Mars probe due to mixing up imperial and metric measurements and then ends with discussion of some of the larger metric prefixes. Listen here
Curriculum Tags: Gr7, Gr8, MPM2P, MBF3C http://www.bbc.co.uk/programmes/p05jgh5y

I like when @ddmeyer releases his yearly talk video. In this one the theme is that "math is power, not punishment". That is, we need to do a better job of convincing students that it is worthwhile to know about math. There are some nice examples and even some Ontario teachers make a brief appearance (@MrOrr_Geek, @AlexOverwijk and @Wheeler_Laura). Definitely worth a watch.
Curriculum Tags: All http://blog.mrmeyer.com/2017/presentation-math-is-power-not-punishment/

Some nice interactives from @dpscher on arrays and a nice video to go along with it from @JamesTanton giving a reason to use arrays in the first place (including for algebra)
Curriclum Tags: All http://www.sineofthetimes.org/multiplication-arrays/

I have seen this Shell Centre activity before but I really like this Desmos update from @pejorgens. It's a great way to start kids on interpreting points on a scatter plot. Thanks to @mrOrr_Geek for pointing this one out.
Curriculum Tags: Gr8, MPM1D, MFM1P, MDM4U, MAP4C https://teacher.desmos.com/activitybuilder/custom/599ae3856ea0c23e58022e50

I like this problem that @FawnpNguyen highlighted on her blog recently:

There are 75 olives, 40% of which are green. I eat some of the green olives until 10% of the olives that remain are green. How many green olives did I eat?

Specifically I like the way she used a visual solution rather than an algebraic solution. Take a look
Curriculum Tags: Gr7, Gr8, MPM1D, MFM1P http://fawnnguyen.com/green-olives/

If you are talking about scale diagrams with your kids then maybe start by showing what @colin_furze created by starting with a scale model
Curriculum Tags: Gr7, Gr8, MFM1P https://www.youtube.com/watch?v=sTvY9Llqtms

We've been doing a lot of work in our school board on building thinking classrooms. So this post from @BenOrlin is quite timely. It's hard to get your kids to think and he suggest three strategies to make it happen. Check the post out for the full story.
Curriculum Tags: All https://mathwithbaddrawings.com/2017/12/06/the-three-barriers-to-deep-thinking-in-school/

Although this post is a year old, I just saw it for the first time this week. Here @Anniekperkins takes the idea that mathematicians aren't just white dudes to new heights. She drops the following challenge: "Take 10-15 minutes a week to research (read Wikipedia, that’s all you need) a not-old-dead-white-dude mathematician, and then take 5 minutes in class to tell your students about them. " And then she's done most of the work for you. Lists and links of tonnes of mathematicians of all types. Thanks to @ddmeyer for this one.
Curriculum Tags: All https://arbitrarilyclose.com/2016/08/21/the-mathematicians-project-mathematicians-are-not-just-white-dudes/

We have been creating these continuums of math problems on different topics at different grade levels. We have found that students actually really like working on them as practice. We have literally heard them say "Am I sick? Because I think this is fun". In this case, the topic is solving rational equations and inequalities.
Curriculum Tags: MHF4U http://engaging-math.blogspot.ca/2017/11/rational-functions-continuum.html

In a recent podcast from More or Less they look at the possible reason that albums are getting longer. The short answer is - more tracks means more potential clicks and higher chart placing. There is some interesting info about Spotify. I'm thinking you could have some conversations about rate using the information here about things like how many clicks is equated to one "purchase" - 1500 plays equates to one record sale. Listen at the link below
Curriculum Tags: Gr7, Gr8, MPM1D, MFM1P http://www.bbc.co.uk/programmes/p05mpr59

On the Podcast, My Favourite Theorem they interview mathematicians and ask what their favourite theorem is. Though the theorems are not always k-12 centric, on this recent episode you find out how this mathematician connects Pythagorean Theorem with his Navajo identity.
Curriculum Tags: Gr8, MPM1D, MFM1P, MPM2D, MFM2P https://blogs.scientificamerican.com/roots-of-unity/henry-fowlers-favorite-theorem/

I've mentioned John Urschel before. He's the NFL player and MIT PHD math student who quit pro football once the data started coming out on the connection to brain damage and the NFL. Here's a recent story about why he chose math over football.
Curriculum Tags: All https://www.si.com/nfl/2017/11/21/john-urschel-nfl-ravens-mit-mathematics

I have been meaning to try the Mathies Notepad App for a while. So I made this (long) video on dividing fractions using a numberline to do so.
Curriculum Tags: Gr7, Gr8 https://www.youtube.com/watch?v=oD9qSCNUFjs

Do you want to have a bit of fun with students and formulas. Try this:
Curriculum Tags: Gr7, Gr8 https://xkcd.com/1923/

When teachers create activities to share, that's where the Internet is great. I have said that a few times on this blog and I especially like when those activities are for senior math courses. Sometimes we forget that senior students need to have activities too. In this activity, @MaryBourassa has done the leg work for creating logarithmic functions by creating cards of several functions. That's the hard work. The easy bit is giving each function to groups of students and having them determine their function's equation.
Curriculum Tags: MHF4U http://marybourassa.blogspot.ca/2017/11/log-graphs.html

An interesting post from @ddmeyer which is essentially a call to arms in revamping the curriculum. The idea is that currently its designed with very few in mind:

"And just as the economic 1% creates systems that preserve its status – policies like the mortgage interest deduction for homeowners, discriminatory lending policies, and lower taxes on capital gains than income – through our action or inaction we create systems that preserve our status as the knowers and doers of mathematics."