Open Middle Math Depth of Knowledge Matrices by @robertkaplinsky

Open Middle Math Depth of Knowledge Matrices by @robertkaplinsky

Guest Blog post by Robert Kaplinsky

Ready for a problem that will make you rethink how we teach students mathematics?  Try solving the fourth grade problem below in less than three attempts.

Using the digits 1 to 9 at most one time each, place a digit in each box to create a fraction that’s as close to one as possible.  

For example, you could use the 1, 2, 3, and 4 to make the fraction 12/34.  Is that as close to one as you can get?  Also, this is not the Price is Right so a little over 1 and a little under 1 are both great.  Good luck!

Open Middle Problems

We call these kinds of problem Open Middle problems and there are hundreds of them available for you to use for free on openmiddle.com.  Below you’ll see matrices that compare traditionally used problems to Open Middle problems.  Use the button below to download high quality, printable PDFs of all of them or preview what you’ll get by scrolling below.

Preview

Elementary & Secondary Matrix

Elementary Matrix (K-5)

Secondary Matrix (6 – Calculus)

Third Grade Matrix

Fourth Grade Matrix

Fifth Grade Matrix

Sixth Grade Matrix

Seventh Grade Matrix

Eighth Grade Matrix

Algebra 1 Matrix

Geometry Matrix

Algebra 2 Matrix

Leave a Comment

© 2026 All Rights Reserved.

💥 FREE OTIS WORKSHOP

Join Alice Keeler, Thursday April 15th or register to gain access to the recording.
Create a free OTIS account.

Join Alice Keeler for this session for teaching with AI

Unlock a smarter way to manage your curriculum by turning your own teaching materials into a personalized AI assistant with NotebookLM. This session explores how to transform static documents into interactive study guides and audio overviews that are tailored strictly to your specific content. You will discover how this versatile note-taking tool can streamline your prep time and help you organize complex resources with ease. Join us to see how NotebookLM can act as a powerful, free partner in your K-12 classroom.

Exit this pop up by pressing escape or clicking anywhere off the pop up.