Robert Kaplinsky
@robertkaplinsky.com
Math educator. Love helping teachers.
Open Middle co-founder. #OpenMiddleBook author. #ObserveMe creator. Grassroots Workshops President. Get lessons & ideas: http://bit.ly/rkupdates
Open Middle co-founder. #OpenMiddleBook author. #ObserveMe creator. Grassroots Workshops President. Get lessons & ideas: http://bit.ly/rkupdates
Here's a challenging Open Middle problem to help students develop conceptual understanding of quadratics in standard form: www.openmiddle.com/maximum-...
February 9, 2026 at 11:33 PM
Here's a challenging Open Middle problem to help students develop conceptual understanding of quadratics in standard form: www.openmiddle.com/maximum-...
Here are some examples of what Depth of Knowledge looks like in high school mathematics. Check out and download my Secondary Math DOK matrix.
robertkaplinsky.com/depth-k...
robertkaplinsky.com/depth-k...
February 9, 2026 at 5:03 PM
Here are some examples of what Depth of Knowledge looks like in high school mathematics. Check out and download my Secondary Math DOK matrix.
robertkaplinsky.com/depth-k...
robertkaplinsky.com/depth-k...
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...
robertkaplinsky.com/work/ho...
February 9, 2026 at 12:13 AM
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...
robertkaplinsky.com/work/ho...
As a teacher specialist, I never had time to set classroom norms when I worked with new students. So, here's how I set them in 30 seconds.
robertkaplinsky.com/30-seco...
robertkaplinsky.com/30-seco...
February 8, 2026 at 1:13 AM
As a teacher specialist, I never had time to set classroom norms when I worked with new students. So, here's how I set them in 30 seconds.
robertkaplinsky.com/30-seco...
robertkaplinsky.com/30-seco...
If you wish your students had better number sense, then you'll love the estimation tasks from Andrew Stadel on Estimation 180. Here are the first twenty to get you started.
estimation180.com/days-1-20/
estimation180.com/days-1-20/
February 7, 2026 at 8:07 PM
If you wish your students had better number sense, then you'll love the estimation tasks from Andrew Stadel on Estimation 180. Here are the first twenty to get you started.
estimation180.com/days-1-20/
estimation180.com/days-1-20/
Check out the professional development options on Grassroots Workshops (@grassrootsworkshops.com). There are flexible online workshops on topics including mathematics, social justice, teaching online, coding, English, wellness, and science.
grassrootsworkshops.com/
grassrootsworkshops.com/
February 7, 2026 at 5:45 PM
Check out the professional development options on Grassroots Workshops (@grassrootsworkshops.com). There are flexible online workshops on topics including mathematics, social justice, teaching online, coding, English, wellness, and science.
grassrootsworkshops.com/
grassrootsworkshops.com/
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...
February 6, 2026 at 11:43 PM
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...
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...
robertkaplinsky.com/work/dr...
February 6, 2026 at 8:07 PM
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...
robertkaplinsky.com/work/dr...
Could it be that we're creating an army of math robots rather than deep mathematical thinkers? I've got an experiment for you that may make you question what you know.
robertkaplinsky.com/robots-...
robertkaplinsky.com/robots-...
February 5, 2026 at 11:34 PM
Could it be that we're creating an army of math robots rather than deep mathematical thinkers? I've got an experiment for you that may make you question what you know.
robertkaplinsky.com/robots-...
robertkaplinsky.com/robots-...
Reposted by Robert Kaplinsky
If you've wanted to teach math using real-world and Open Middle problems but want support getting started, then this is the workshop for you.
Learn more about Robert Kaplinsky's @robertkaplinsky.com Empowered Problem Solving online workshop at grassrootsworkshops.com/wor...
Learn more about Robert Kaplinsky's @robertkaplinsky.com Empowered Problem Solving online workshop at grassrootsworkshops.com/wor...
February 4, 2026 at 12:13 AM
If you've wanted to teach math using real-world and Open Middle problems but want support getting started, then this is the workshop for you.
Learn more about Robert Kaplinsky's @robertkaplinsky.com Empowered Problem Solving online workshop at grassrootsworkshops.com/wor...
Learn more about Robert Kaplinsky's @robertkaplinsky.com Empowered Problem Solving online workshop at grassrootsworkshops.com/wor...
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...
www.openmiddle.com/equation...
www.openmiddle.com/equation...
February 5, 2026 at 1:10 AM
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...
www.openmiddle.com/equation...
www.openmiddle.com/equation...
If you teach 3rd or 4th grade and are looking for a real world context for adding time, then check out this lesson that uses the context of a road trip and GPS navigation to estimate an arrival time.
robertkaplinsky.com/work/ar...
robertkaplinsky.com/work/ar...
February 4, 2026 at 11:14 PM
If you teach 3rd or 4th grade and are looking for a real world context for adding time, then check out this lesson that uses the context of a road trip and GPS navigation to estimate an arrival time.
robertkaplinsky.com/work/ar...
robertkaplinsky.com/work/ar...
Reposted by Robert Kaplinsky
Want to teach math using real-world and @openmiddle.com problem solving? Would you like support getting started?
Register for Robert Kaplinsky's @robertkaplinsky.com Empowered Problem Solving online workshop by Fri 2/6.
grassrootsworkshops.com/wor...
Register for Robert Kaplinsky's @robertkaplinsky.com Empowered Problem Solving online workshop by Fri 2/6.
grassrootsworkshops.com/wor...
February 2, 2026 at 7:36 PM
Want to teach math using real-world and @openmiddle.com problem solving? Would you like support getting started?
Register for Robert Kaplinsky's @robertkaplinsky.com Empowered Problem Solving online workshop by Fri 2/6.
grassrootsworkshops.com/wor...
Register for Robert Kaplinsky's @robertkaplinsky.com Empowered Problem Solving online workshop by Fri 2/6.
grassrootsworkshops.com/wor...
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...
www.openmiddle.com/creating...
www.openmiddle.com/creating...
www.openmiddle.com/creating...
February 2, 2026 at 11:33 PM
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...
www.openmiddle.com/creating...
www.openmiddle.com/creating...
www.openmiddle.com/creating...
Here's my breakdown on the differences (including strengths and weaknesses) between #ObserveMe and Pineapple Charts.
robertkaplinsky.com/whats-d...
robertkaplinsky.com/whats-d...
February 2, 2026 at 5:03 PM
Here's my breakdown on the differences (including strengths and weaknesses) between #ObserveMe and Pineapple Charts.
robertkaplinsky.com/whats-d...
robertkaplinsky.com/whats-d...
Want a fun (and gross) context for teaching linear and quadratic functions from a table of values? Check out this lesson and video featuring two competitive eaters to figure out how many hot dogs they've each eaten.
robertkaplinsky.com/work/ho...
robertkaplinsky.com/work/ho...
February 2, 2026 at 12:13 AM
Want a fun (and gross) context for teaching linear and quadratic functions from a table of values? Check out this lesson and video featuring two competitive eaters to figure out how many hot dogs they've each eaten.
robertkaplinsky.com/work/ho...
robertkaplinsky.com/work/ho...
What can a horse that could add, subtract, multiply, and divide teach us about how we ask our students questions?
robertkaplinsky.com/never-a...
robertkaplinsky.com/never-a...
February 1, 2026 at 1:13 AM
What can a horse that could add, subtract, multiply, and divide teach us about how we ask our students questions?
robertkaplinsky.com/never-a...
robertkaplinsky.com/never-a...
Graham Fletcher's progression video explains how students learn multiplication from 2nd through 5th grade. It applies just as importantly to middle and high school teachers (distributive property, polynomial multiplication, etc.).
Watch it here: gfletchy.com/multiplication...
Watch it here: gfletchy.com/multiplication...
January 31, 2026 at 8:07 PM
Graham Fletcher's progression video explains how students learn multiplication from 2nd through 5th grade. It applies just as importantly to middle and high school teachers (distributive property, polynomial multiplication, etc.).
Watch it here: gfletchy.com/multiplication...
Watch it here: gfletchy.com/multiplication...
If you provide online professional development, you should check out my webinar called "Six Counterintuitive Lessons Learned About Online Workshops". For example, should they be more like Netflix or traditional TV?
Watch here: https://info.robertkaplinsky.com/counterintuitive/
Watch here: https://info.robertkaplinsky.com/counterintuitive/
January 31, 2026 at 5:45 PM
If you provide online professional development, you should check out my webinar called "Six Counterintuitive Lessons Learned About Online Workshops". For example, should they be more like Netflix or traditional TV?
Watch here: https://info.robertkaplinsky.com/counterintuitive/
Watch here: https://info.robertkaplinsky.com/counterintuitive/
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-...
www.openmiddle.com/complex-...
www.openmiddle.com/complex-...
January 30, 2026 at 11:43 PM
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-...
www.openmiddle.com/complex-...
www.openmiddle.com/complex-...
How do you figure out the distances that should be listed on a freeway sign? This lesson uses a picture of a freeway sign with missing distances and a map with where the freeway sign is located to provide a context for determining those distances.
robertkaplinsky.com/work/wh...
robertkaplinsky.com/work/wh...
January 30, 2026 at 8:07 PM
How do you figure out the distances that should be listed on a freeway sign? This lesson uses a picture of a freeway sign with missing distances and a map with where the freeway sign is located to provide a context for determining those distances.
robertkaplinsky.com/work/wh...
robertkaplinsky.com/work/wh...
Have you ever felt like your school/district makes its employees do so much that everyone burns out?
If so, this blog post's for you: robertkaplinsky.com/read-te...
If so, this blog post's for you: robertkaplinsky.com/read-te...
January 29, 2026 at 11:34 PM
Have you ever felt like your school/district makes its employees do so much that everyone burns out?
If so, this blog post's for you: robertkaplinsky.com/read-te...
If so, this blog post's for you: robertkaplinsky.com/read-te...
Help your students think deeply about radicals with this Open Middle problem from Phillip Haislip-Hansberry. www.openmiddle.com/comparin...
January 29, 2026 at 1:10 AM
Help your students think deeply about radicals with this Open Middle problem from Phillip Haislip-Hansberry. www.openmiddle.com/comparin...
How many times will a case of paper jam when it's advertised as 99.99% jam-free? I wish it better matched my own experience with copy machines!
robertkaplinsky.com/work/ho...
robertkaplinsky.com/work/ho...
January 28, 2026 at 11:14 PM
How many times will a case of paper jam when it's advertised as 99.99% jam-free? I wish it better matched my own experience with copy machines!
robertkaplinsky.com/work/ho...
robertkaplinsky.com/work/ho...
If your students are learning about perpendicular lines, try out this Open Middle problem from Andy Schwen with them: www.openmiddle.com/perpendi...
January 26, 2026 at 11:33 PM
If your students are learning about perpendicular lines, try out this Open Middle problem from Andy Schwen with them: www.openmiddle.com/perpendi...