Math educator. Love helping teachers. Open Middle co-founder. #OpenMiddleBook author. #ObserveMe creator. Grassroots Workshops President. Get lessons & ideas: http://bit.ly/rkupdateshttps://bsky.app/profile/robertkaplinsky.comhttps://bsky.app/profile/robertkaplinsky.com/post/3mk72zfpzlp2sAs a student, I was a math robot. I could answer problems without understanding the story of math and how the different concepts connected to one another. Now I see math teachers' job as telling the story of mathematics. https://robertkaplinsky.com/math-teachers-are-storytellers/23 Apr 2026 22:34 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mk72zfpzlp2shttps://bsky.app/profile/robertkaplinsky.com/post/3mk4pw55tbl24How 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: http://www.openmiddle.com/perpendicular-lines-and-slope/ http://www.openmiddle.com/parallel-lines-and-slope/23 Apr 2026 00:10 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mk4pw55tbl24https://bsky.app/profile/robertkaplinsky.com/post/3mk4jgpyr6f2vI have over 70 real world problem-based lessons from kindergarten through high school that you can download for free and use with your students. Check them out and let me know which are your favorites in the comments. robertkaplinsky.com/lessons22 Apr 2026 22:14 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mk4jgpyr6f2vhttps://bsky.app/profile/robertkaplinsky.com/post/3mjxjktsjeu22Are your students learning about parallel lines and transversals? Try out these two Open Middle problems from Shelli Foust: http://www.openmiddle.com/parallel-lines-and-transversals/ http://www.openmiddle.com/parallel-lines-and-perpendicular-transversals/20 Apr 2026 22:33 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjxjktsjeu22https://bsky.app/profile/robertkaplinsky.com/post/3mjwtri6jbx2xRide sharing apps like Uber calculate your fare using mathematical modeling. What info do they need to make a fair estimate (Spies) and what would they do with that info to calculate the dollar amount (Analysts)? https://robertkaplinsky.com/math-modeling-can-tell-uber-much-charge/20 Apr 2026 16:03 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjwtri6jbx2xhttps://bsky.app/profile/robertkaplinsky.com/post/3mjv3dhikkq2jWant to challenge your 8th grade or Geometry students? This lesson uses an intriguing picture of a lawn with circles on it to talk about solutions that will water all of the grass. https://robertkaplinsky.com/work/water-grass/19 Apr 2026 23:13 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjv3dhikkq2jhttps://bsky.app/profile/robertkaplinsky.com/post/3mjso7szy4p2eIf you're a teacher who works outside the classroom, you must read this blog post. I spent eight years as a math teacher specialist at a public school district and sometimes it felt like purgatory. Here's what I've learned during that time. https://robertkaplinsky.com/what-ive-learned-from-being-a-math-teacher-specialist/19 Apr 2026 00:13 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjso7szy4p2ehttps://bsky.app/profile/robertkaplinsky.com/post/3mjs54nmw7x24Are you an elementary teacher looking for some images you can bring into your math classroom to get kids talking? Check out Math Visuals from Berkeley Everett: mathvisuals.wordpress.com/18 Apr 2026 19:07 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjs54nmw7x24https://bsky.app/profile/robertkaplinsky.com/post/3mjrv6qs2w624Tired of students getting correct answers, yet not really understanding what they're doing? Then you should check out the recording of my How To Help Students Become Problem Solvers, Not Math Robots webinar with K-5 & 6-12 versions. https://robertkaplinsky.com/norobotswebinar18 Apr 2026 16:45 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjrv6qs2w624https://bsky.app/profile/robertkaplinsky.com/post/3mjpypxlyib2gWant to challenge your Geometry students to find the area of triangles? Try out this Open Middle problem from Dan Wulf. http://www.openmiddle.com/area-of-three-triangles/17 Apr 2026 22:43 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjpypxlyib2ghttps://bsky.app/profile/robertkaplinsky.com/post/3mjpmnqw3ff2jLooking for a real world context for multiplying and dividing decimals? Check out my problem-based lesson called How Much Money Do You Earn For 1,000,000 Streams On Spotify? https://robertkaplinsky.com/work/how-much-money-do-you-earn-for-1000000-streams-on-spotify/17 Apr 2026 19:07 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjpmnqw3ff2jhttps://bsky.app/profile/robertkaplinsky.com/post/3mjp7qaz4522uWho else has read the Dungeon Crawler Carl book series besides @sweenwsweens.bsky.social? I'm literally addicted to it. Like I don't want to work or do anything but read the rest of book 5. I am not looking forward to the withdrawal that will come when there are no more books to read. 😱😱💀💀☠️☠️17 Apr 2026 15:15 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjp7qaz4522uhttps://bsky.app/profile/robertkaplinsky.com/post/3mjnhrghoj62pCould having the same person teach students AND make the assessments lead to false positives results? https://robertkaplinsky.com/fire-extinguishers-can-teach-us-making-assessments/16 Apr 2026 22:34 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjnhrghoj62phttps://bsky.app/profile/robertkaplinsky.com/post/3mjl4noyrbn25Here's a challenging Open Middle problem to help students develop conceptual understanding of quadratics in standard form: http://www.openmiddle.com/maximum-value-of-a-quadratic-in-standard-form/16 Apr 2026 00:10 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjl4noyrbn25https://bsky.app/profile/robertkaplinsky.com/post/3mjkw6biqx22eHere's a lesson to help elementary students apply their skills with perimeter, measurement, and scale by finding how many laps around a park it takes to run a 5k race. https://robertkaplinsky.com/work/5k-race/15 Apr 2026 22:14 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjkw6biqx22ehttps://bsky.app/profile/robertkaplinsky.com/post/3mjfwcfgwpr2dIf your Geometry students are working on the midpoint formula, try out this Open Middle problem from Dane Ehlert with them. http://www.openmiddle.com/midpoint-formula/13 Apr 2026 22:33 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjfwcfgwpr2dhttps://bsky.app/profile/robertkaplinsky.com/post/3mjfaj2e6x22eIf you're tired of people saying that they lecture in middle school to prepare students for more lecture in high school and college, then you may enjoy my thoughts on this (absurd) topic. https://robertkaplinsky.com/prepare-students-lectures/13 Apr 2026 16:03 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjfaj2e6x22ehttps://bsky.app/profile/robertkaplinsky.com/post/3mjdi2z5jjj25How do you count money when there was so much that it was “world's largest drug bust?” This is a great opportunity to help students develop and apply using volume of rectangular prisms. https://robertkaplinsky.com/work/drug-money/12 Apr 2026 23:13 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjdi2z5jjj25https://bsky.app/profile/robertkaplinsky.com/post/3mjb2xeuht42dI asked 383 US math teachers if they had enough time to teach all their standards in one year. Here's what they said: https://robertkaplinsky.com/enough-time-teach-standards-one-year/12 Apr 2026 00:13 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjb2xeuht42dhttps://bsky.app/profile/robertkaplinsky.com/post/3mjaju7vxl42dThis 7-minute video on early numeracy and counting from Graham Fletcher is perfect for Pre-K to 1st grade teachers. https://gfletchy.com/progression-of-early-number-and-counting/11 Apr 2026 19:07 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjaju7vxl42dhttps://bsky.app/profile/robertkaplinsky.com/post/3mjabwcitn42sDo you present to other educators or aspire to? I created a webinar where I go through my entire presentation creation process from start to finish. For example, I use this three circle Venn diagram to help me choose a topic. Watch it here: https://info.robertkaplinsky.com/captivating/11 Apr 2026 16:45 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mjabwcitn42shttps://bsky.app/profile/robertkaplinsky.com/post/3mj6fhjar4s2eAre your students working on parallel and perpendicular lines? Try out these two Open Middle problems from Bryan Anderson: http://www.openmiddle.com/equations-of-perpendicular-lines/ http://www.openmiddle.com/equations-of-parallel-lines/10 Apr 2026 22:43 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mj6fhjar4s2ehttps://bsky.app/profile/robertkaplinsky.com/post/3mj5zfc6oc22rHow many movies can you see in one day? This lesson is perfect for third and fourth graders who are working on operations with time. I've included four different movie schedule options that range from easy to very challenging. https://robertkaplinsky.com/work/movies/10 Apr 2026 19:07 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mj5zfc6oc22rhttps://bsky.app/profile/robertkaplinsky.com/post/3mj3uijgvzt2sI think that many schools and districts have mission and vision statements that are essentially useless but no one wants to admit it. Read more: https://robertkaplinsky.com/read-this-before-writing-another-call-to-action-or-mission-statement/09 Apr 2026 22:34 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mj3uijgvzt2shttps://bsky.app/profile/robertkaplinsky.com/post/3mizjfb2l7j2mCan 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. http://www.openmiddle.com/creating-right-triangles/ http://www.openmiddle.com/creating-parallelograms/ http://www.openmiddle.com/creating-parallelograms-2/09 Apr 2026 00:10 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mizjfb2l7j2mhttps://bsky.app/profile/robertkaplinsky.com/post/3mizcvthi5o2sIf you also like a good prank, then you'll love this lesson on surface area. It uses the aluminum foil prank to figure out how much it would cost to cover a room of your choosing. It's a great way to build conceptual understanding using nets. https://robertkaplinsky.com/work/foil-prank/08 Apr 2026 22:14 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mizcvthi5o2shttps://bsky.app/profile/robertkaplinsky.com/post/3miuczxe7sh2mAre your high school students working with complex numbers? Try these two Open Middle problems out to see what misconceptions they have: http://www.openmiddle.com/complex-number-products/ http://www.openmiddle.com/complex-number-products-greatest-value/06 Apr 2026 22:33 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3miuczxe7sh2mhttps://bsky.app/profile/robertkaplinsky.com/post/3mitnalmc4i2lI'm a huge fan of the research around growth mindset, but there is one part that I'd like to explore: do you really learn from mistakes that you're not aware of? https://robertkaplinsky.com/really-learn-dont-realize-youve-made-mistake/06 Apr 2026 16:03 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3mitnalmc4i2lhttps://bsky.app/profile/robertkaplinsky.com/post/3miruskvbtv2lA homeowner beautifully tiled her floor with about 13,000 pennies. Everyone thought it was wonderful... but then people complained on social media about how she wasted $13,000! 🤦‍♂️ https://robertkaplinsky.com/work/much-money-pennies/05 Apr 2026 23:13 +0000at://did:plc:ulnupdziw5vvk2aryf5gdpwe/app.bsky.feed.post/3miruskvbtv2l