This week, I came across the treasure trove of problems available at **ssddproblems.com**, created and curated by Craig Barton. SSDD stands for “Same Surface, Different Deep” and each set of problems contains four questions that have a similar presentation (a common image, shape, or context) but where the deep mathematical structures of the problems are very different¹.

SSDD problems are the essence of “Interleaving Different Practice”, one of the techniques that enhances learning from the book **Make It Stick: The Science of Successful Learning**². Page 85 explains how interleaving fosters conceptual understanding:

The trouble with interleaving is that it can actually impede initial learning, which is one reason teachers might not gravitate to the technique; however, the research “shows unequivocally that mastery and long-term retention are much better if you interleave practice than if you mass it.” (p. 50) [massed practice is focused, repetitive practice of one thing at a time.]

Craig’s SSDD problems are based on extensive cognitive science research showing that this strategy of interleaved practice is beneficial to learning by helping students discriminate between problem types and choose appropriate strategies to solve based on the underlying deep structure. He says this is in contrast to the “auto-pilot” approach that can be common with students: they see a right triangle and jump right to the Pythagorean Theorem, whether or not it is useful. Here is one of his question sets involving right triangles:

Students working on “auto-pilot” is one consequence of how we often teach math topics: practicing similar types of problems in a given lesson, then moving on to another type, then another. When students are faced with cumulative tests or spiral review problems, they might not remember what they had “mastered” earlier.

Of course, I wanted to get in on the fun! Craig **tweeted** yesterday that in the prior 5 days, his website grew from 80 question sets to 200 sets. He has a helpful template available for creating an SSDD powerpoint slide. I scanned the list of topics on the website, looking for something fruitful that could also capitalize on technology and connect various representations, and didn’t yet have several sets posted. I developed this question set on Quadratic Graphs:

My process was this: I first brainstormed the types of questions that could get asked about a quadratic graph. By the time Algebra 1 or Algebra 2 students are done with a unit on quadratics, they have covered a lot of ground, and can be confused by different forms of quadratic functions or when to use various solving techniques.

I decided that my focus would be on examining features of the graph to write different forms of the quadratic function, or use the graph’s features to solve equations and real-context problems.

It was challenging to choose one graph that could work for all these purposes:

- Determine Vertex Form from a graph (and with
*a*≠ 0 to increase cognitive demand) - Determine Factored Form from a graph (required relating zeros of the function to its factors, again with
*a*≠ 0) - Use a graph to Solve an Equation (either find points of intersection with technology, or solve using quadratic formula; including simplifying radicals to exact form or finding decimal approximations)
- Interpret a Graph in a Real Context (with different scales on horizontal and vertical axes)

I took screenshots from TI-84+CE SmartView Emulator software³. The color and graph grid makes it possible for students to gather information by inspection and not have to rely on the calculator to analyze the graph’s features. I’m pleased with how the problems turned out; any feedback is welcome.

You can find my set on **ssddproblems.com** under the topic “**Equation of a Quadratic Curve**” or **this direct link** and the original powerpoint is **here**. One caveat to keep in mind about the problem sets on the SSDD site is that Craig works in England; there are some differences in vocabulary between American math and British maths, with both represented on the site.

I am excited about diving in to the rich resource at **ssddproblems.com** and looking below the surface for deeper learning! Join me…

**Notes and Resources:**

1. There is much more background explanation about the SSDD problems and their research base on Craig’s **website**. They were introduced in his book “**How I Wish I Taught Maths: Lessons Learned from Research, Conversations with Experts and 12 Years of Mistakes**” (2018).

2. The book “**Make It Stick: The Science of Successful Learning**” by Brown, Roediger & McDaniel (2014) has a companion website **MakeItStick.net**. The authors advocate for the strategies of spaced and interleaved retrieval practice, elaboration, generation, reflection, and calibration in order to optimize learning. Another helpful blog post by Debbie Morrison about using these techniques in your teaching is **here**.

3. More information about the TI-SmartView CE Emulator Software for the entire TI-84+ family can be found on the TI Website **here**. Currently there is a 90-day free trial available. Take advantage of color demonstrations for your class, save work in progress, and insert screenshots and keystrokes in your handouts and assessments.

4. Michael Pershan wrote **this blog post** with his thoughts on the SSDD problem sets. He focused on geometry diagrams, for which I think the SSDD sets are extremely well suited.