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Robert Kaplinsky @robertkaplinsky.com · 13h

Want to challenge your Geometry students to find the area of triangles? Try out this Open Middle problem from Dan Wulf. www.openmiddle.com/area-of-...

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Robert Kaplinsky @robertkaplinsky.com · 15h

Looking for a real world context for writing out numbers in expanded form? This problem uses check writing to help kids make sense of the process. Share it with an elementary teacher you know. robertkaplinsky.com/work/wr...

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Robert Kaplinsky @robertkaplinsky.com · 28/09/2026

Here's a challenging Open Middle problem to help students develop conceptual understanding of quadratics in standard form: www.openmiddle.com/maximum-...

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Robert Kaplinsky @robertkaplinsky.com · 28/09/2026

Here's my letter to the editor published in Education Week about why math educators should use social media professionally. robertkaplinsky.com/letter-...

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Robert Kaplinsky @robertkaplinsky.com · 28/09/2026

This lesson uses a BuzzFeed video to help students better visualize calories. It's also a great context for combining like terms and solving one- and two-step equations: robertkaplinsky.com/work/wh...

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Robert Kaplinsky @robertkaplinsky.com · 27/09/2026

I used to think that courageous and fearless were interchangeable. They're not and I unpack the meaningful difference in this really short blog post. robertkaplinsky.com/be-cour...

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Robert Kaplinsky @robertkaplinsky.com · 26/09/2026

Math openers promote rigorous student thinking and discourse at the beginning of each class. Dan Finkel from Math for Love provides over a dozen free openers on his website: mathforlove.com/lessons/ope... And here's his online workshop on openers: grassrootsworkshops.com/wor...

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Robert Kaplinsky @robertkaplinsky.com · 26/09/2026

If you teach others through online workshops, then you should check out my webinar recording on 6 counterintuitive lessons learned I wish I had understood earlier. For example, should workshops feel more like watching Netflix or traditional TV? robertkaplinsky.com/pdwebinar

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Reposted by Robert Kaplinsky

Jennifer Lempp @jennifer-lempp.bsky.social · 22/09/2026

Are you using Open Middle problems in your class? The amount of math students do with one simple problem is amazing. And they are so much more engaging There are so many available at openmiddle.com. I used one with my undergraduates last night. Thanks @robertkaplinsky.com for this amazing resource!

Undergraduate students solving an open middle problem

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Robert Kaplinsky @robertkaplinsky.com · 25/09/2026

If your Geometry students are working on the midpoint formula, try out this Open Middle problem from Dane Ehlert with them. www.openmiddle.com/midpoint...

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Robert Kaplinsky @robertkaplinsky.com · 25/09/2026

Did you know that Hyundai offers a 100,000 mile in countries that use miles and 100,000 km warranty in countries that use the metric system? Are they the same? If not, which is better for the consumer and which is better for Hyundai? robertkaplinsky.com/work/ca...

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Robert Kaplinsky @robertkaplinsky.com · 24/09/2026

Teach high school math? Check out this blog post for a quick tip to identify which standards require mathematical modeling. robertkaplinsky.com/high-sc...

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Robert Kaplinsky @robertkaplinsky.com · 24/09/2026

Are your students working on parallel and perpendicular lines? Try out these two Open Middle problems from Bryan Anderson: www.openmiddle.com/equation... www.openmiddle.com/equation...

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Robert Kaplinsky @robertkaplinsky.com · 23/09/2026

Have you ever noticed that pipes can be stacked in staggered or non-staggered stacks? Staggered stacks are shorter, but calculating exactly how much shorter is not easy. This problem can be solved using the Pythagorean Theorem or trig ratios. robertkaplinsky.com/work/st...

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Robert Kaplinsky @robertkaplinsky.com · 21/09/2026

Can your high school students create a parallelogram, triangle, or rectangle by listing their points when given one? Find out using these three Open Middle problem from Bryan Anderson. www.openmiddle.com/creating... www.openmiddle.com/creating... www.openmiddle.com/creating...

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Robert Kaplinsky @robertkaplinsky.com · 21/09/2026

Here are some examples of what higher Depth of Knowledge math problems look like in middle school. Check out and download my Secondary Math DOK matrix. robertkaplinsky.com/depth-k...

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Robert Kaplinsky @robertkaplinsky.com · 21/09/2026

Help students appreciate the magnitude of the problem that littered cigarette butts cause on a daily basis by applying what they know about volume. robertkaplinsky.com/work/ci...

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Robert Kaplinsky @robertkaplinsky.com · 20/09/2026

Here are examples of what higher Depth of Knowledge math problems look like in 3rd to 5th grade. Check out and download my K-5 Elementary Math DOK matrix. robertkaplinsky.com/depth-k...

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Robert Kaplinsky @robertkaplinsky.com · 19/09/2026

If you haven't bought a copy of "Which One Doesn't Belong from @Trianglemancsd, you have to here: amzn.to/4c3mTLp. So many great conversations to have! My then 8 year old son said that the bottom left one did not belong "because it's the only muffin shape."

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Robert Kaplinsky @robertkaplinsky.com · 19/09/2026

If you have a website (or are planning on making one), you should check out my webinar on three things your website should include and one you should avoid. The examples are specific to educational consulting, but apply to all websites. info.robertkaplinsky.com/we...

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Robert Kaplinsky @robertkaplinsky.com · 18/09/2026

Are your high school students working with complex numbers? Try these two Open Middle problems out to see what misconceptions they have: www.openmiddle.com/complex-... www.openmiddle.com/complex-...

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Robert Kaplinsky @robertkaplinsky.com · 18/09/2026

A man in Finland received a speeding ticket and had to pay $103,000! The penalty was so harsh because fines in Finland are based not just on the severity of the offense, but on the offender’s income. Can students figure out Vanjoki’s annual income? robertkaplinsky.com/work/fi...

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Robert Kaplinsky @robertkaplinsky.com · 17/09/2026

Here's my article for Education Week on the similarities between healthy eating and math education. robertkaplinsky.com/food-fo...

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Robert Kaplinsky @robertkaplinsky.com · 17/09/2026

Help your students think deeply about radicals with this Open Middle problem from Phillip Haislip-Hansberry. www.openmiddle.com/comparin...

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Robert Kaplinsky @robertkaplinsky.com · 16/09/2026

Looking for a context to teach elementary patterns or high school arithmetic series? We ask elementary students how many Hanukkah candles will we need. We ask high school students how many we would need for n nights. robertkaplinsky.com/work/ho...

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Robert Kaplinsky @robertkaplinsky.com · 14/09/2026

If your students are learning about perpendicular lines, try out this Open Middle problem from Andy Schwen with them: www.openmiddle.com/perpendi...

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Robert Kaplinsky @robertkaplinsky.com · 14/09/2026

Algebra 2 teachers! I've made @openmiddle.com Depth of Knowledge matrices to show how a single problem can replace an entire worksheet in Algebra 2. Download it here: robertkaplinsky.com/depth-o...

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Robert Kaplinsky @robertkaplinsky.com · 14/09/2026

When you're buying peanuts, is it better to buy them in bulk or already bagged? How can you figure out which is the better value? This problem is a context for comparing ratios and unit rates. robertkaplinsky.com/work/pe...

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Robert Kaplinsky @robertkaplinsky.com · 13/09/2026

Too often in education, leaders are looking for that one breakthrough that leads to amazing results. Unfortunately, that's rarely how it ends up. I'll share a metaphor about chicks hatching that will make this so much clearer: robertkaplinsky.com/why-edu...

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Robert Kaplinsky @robertkaplinsky.com · 12/09/2026

Looking to get kids arguing about math? Check out www.wouldyourathermath.com from John Stevens. Lots of great "Would you rather..." scenarios that require math to win the argument.

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Robert Kaplinsky @robertkaplinsky.com · 12/09/2026

If you're a current or aspiring educational consultant, I made a free webinar all about using email and social media to increase your conference attendance, book/product sales, and promote your work. Watch it here: info.robertkaplinsky.com/emailfunnel

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Robert Kaplinsky @robertkaplinsky.com · 11/09/2026

If your high school students are working on adding vectors, try out this Open Middle problem from Bryan Anderson. www.openmiddle.com/adding-v...

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Robert Kaplinsky @robertkaplinsky.com · 11/09/2026

This lesson uses the context of throwing a baseball as quickly as possible to help students practice ratios, proportions, and converting between units. It's perfect for 6th and 7th graders. robertkaplinsky.com/work/th...

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Robert Kaplinsky @robertkaplinsky.com · 10/09/2026

What's at the center of a three-circle Venn diagram of the Common Core Math and ELA standards with the Next Generation Science Standards? Read more here: robertkaplinsky.com/how-do-...

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Robert Kaplinsky @robertkaplinsky.com · 10/09/2026

Here's a matrix multiplication problem from Bryan Anderson that will help you bring out their conceptual understanding. See hints and answers on Open Middle. www.openmiddle.com/matrix-m...

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Robert Kaplinsky @robertkaplinsky.com · 09/09/2026

How many square inches is the world's largest deliverable pizza? My favorite part is that one of the answers provided by Modern Marvels in their video clip is actually wrong! It gives students a great opportunity to critique the reasoning of others. robertkaplinsky.com/work/gi...

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Robert Kaplinsky @robertkaplinsky.com · 07/09/2026

Algebra teachers, check out these three rational exponent problems from Bryan Anderson. See the hints and answers on Open Middle: www.openmiddle.com/rational... www.openmiddle.com/rational... www.openmiddle.com/rational...

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Robert Kaplinsky @robertkaplinsky.com · 07/09/2026

What can baking a Pinterest Fail Elmo cake tell us that will help our students become better problem solvers? robertkaplinsky.com/is-prob...

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Robert Kaplinsky @robertkaplinsky.com · 07/09/2026

Does upgrading from a standard model to the hybrid equivalent pays for itself with saved gas money? The problem can be done primarily with rates to make it appropriate for sixth or seventh grade or with systems of equations for Algebra. robertkaplinsky.com/work/hy...

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Robert Kaplinsky @robertkaplinsky.com · 06/09/2026

If you run any kind of educator conference, here are three questions you should be furiously working to answer if you want to stay relevant: robertkaplinsky.com/three-q...

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Robert Kaplinsky @robertkaplinsky.com · 05/09/2026

Have you seen samedifferentimages.wordpre... from Brian Bushart? Same or Different? is a routine that provides students opportunities to construct arguments when comparing objects, such as numbers or shapes.

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Robert Kaplinsky @robertkaplinsky.com · 05/09/2026

If you're an educational consultant who trains other educators, you should join the over one thousand consultants in our community. It's a place to give and get advice from others who get what you're going through. www.facebook.com/groups/edc...

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Robert Kaplinsky @robertkaplinsky.com · 04/09/2026

Are your students working on radical equations? This Open Middle problem from Jonathan Newman will challenge their understandings! www.openmiddle.com/radical-...

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Robert Kaplinsky @robertkaplinsky.com · 04/09/2026

Here's a counting lesson for late kinder and first grade called How Many Ducklings Are There? It uses photos from a Minnesota lake where a mama duck was taking care of 76 ducklings! robertkaplinsky.com/work/ho...

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Robert Kaplinsky @robertkaplinsky.com · 03/09/2026

What can Cookie Monster cupcake Pinterest Fails teach us about potential misinterpretations around Depth of Knowledge? Read more here: robertkaplinsky.com/is-dept...

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Robert Kaplinsky @robertkaplinsky.com · 03/09/2026

How deeply do your students understand parallel and perpendicular lines if they can't create sets of points to define the lines? Try out these two Open Middle problems from Nanette Johnson: www.openmiddle.com/perpendi... www.openmiddle.com/parallel...

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Robert Kaplinsky @robertkaplinsky.com · 02/09/2026

Want an evil way to teach exponential growth? This lesson uses a clip from Austin Powers where Dr. Evil demands far too little money to teach calculating compound interest. robertkaplinsky.com/work/dr...

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Robert Kaplinsky @robertkaplinsky.com · 31/08/2026

Are your students learning about parallel lines and transversals? Try out these two Open Middle problems from Shelli Foust: www.openmiddle.com/parallel... www.openmiddle.com/parallel...

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Robert Kaplinsky @robertkaplinsky.com · 31/08/2026

The first time I put a higher Depth of Knowledge problem on an assessment, I thought it would be no big deal. I was very wrong. Most of the class got it wrong and it opened my eyes. Read more: robertkaplinsky.com/why-doe...

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