In the transition to Citizen Math, we made the hard decision to not update many of our old Mathalicious lessons which are now scheduled for retirement June 1, 2022. We know you have some questions.

Why We Cut Lessons
We know that every day can't (and shouldn't) be a real-world application of mathematics. Over several years, we determined that for most schools and teachers who were consistently and deeply integrating Mathalicious, ideal implementation looked like one or two lessons per major instructional unit.

Each lesson takes a few days, so that represents a significant and memorable chunk of the learning experience. And from a massive research study, we also learned that even a couple of lessons is enough to make a big impact. This means that instead of teaching roughly 18 lessons per course as we originally envisioned, teachers really only needed 6-12 lessons to have a transformative experience.

Too much choice can be overwhelming. To help teachers and administrators successfully incorporate Citizen Math into their core curriculums, we identified the twelve Mathalicious lessons per course that we thought could create the most impactful experience for students. Next, we rebuilt them from scratch. New handouts and narratives. Better teacher guides with richer support. Completely redesigned online interactives. We even adjusted the imagery on the website and in the lessons to be more visually diverse and representative of all students.

At first glance, it may seem strange that we didn't rewrite the entire Mathalicious library. By providing teachers with fewer lessons, though -- and in particular, by prioritizing the best of the best -- we're confident we can help them have an even better classroom experience.

Which Lessons We Kept and Which We Cut

So how did we decide which lessons to rewrite? As we transitioned to Citizen Math, there were three* questions that we asked ourselves when deciding whether or not to rewrite a particular lesson:

  1. Is the issue thought-provoking or societally important?

  2. Can students approach the mathematics in different ways?

  3. Does the driving question have a right answer? (If so, we were less likely to prioritize it.)

Take the lesson "Flicks." In it, students use linear functions to determine which movie rental service is the best deal: Netflix, Redbox, or Apple. Since students can answer the question using tables, graphs, and equations, the lesson satisfied criteria #2. But since it had a definitive answer, and since finding the cheapest service does little to challenge students to think about the world more deeply, it failed criteria #1 and #3. Even though "Flicks" was one of the most popular lessons on Mathalicious, we opted not to rewrite it.

We did, however, rewrite the lesson "Wage War" in which students use linear functions to debate whether the federal government should increase the minimum wage. This easily satisfied criteria #1 and #2. And since the question does not have a definitive answer, it also satisfied criteria #3. So did "Big Foot Conspiracy" in which students discuss whether people with small feet should pay less for shoes. Even though shoe pricing seems like a less urgent issue than the minimum wage, both explorations are equally rich mathematically and have the critical characteristic of helping students think flexibly about the world around them and emerging from math class with a deeper appreciation of the fact that most questions in real life defy a single solution.

Of course, these may seem like strange criteria to use when writing math lessons; they're almost certainly not the criteria that textbook authors use (nor should they be). But that's what makes Citizen Math different. Our lessons don't exist just to help students get better at mastering mathematical procedures or discovering mathematical concepts. They exist to help students use those procedures and concepts to think critically about the world. Gone, then, is the Mathalicious activity in which students use cylinder volume and surface area to compare Crunchy vs. Puffy Cheetos. And back (and better than ever) is the activity in which they analyze the pros and cons of different-sized disposable water bottles and discuss the best strategies for reducing plastic in the ocean. Because Citizen Math serves a different function than other resources do, we must play by different rules.

It may be frustrating to no longer see your favorite Mathalicious lesson on the new Citizen Math site. And we're sorry about that. (Seriously. We love the old lessons, too.) But we're hopeful that you'll agree with the choices we made...especially the next time you're at the beach.

(*In addition to the three criteria described above, there was a fourth question that we considered when deciding whether or not to rewrite a lesson: Can the lesson serve as a jumping-off point for larger experiences? In the lesson "Hair Today, Gone Tomorrow," students graph and solve equations to determine how long it takes to donate hair to Locks of Love. When they do, they discover that it would take a single person nearly twenty years to donate an entire wig. After students do this lesson, we thought, wouldn't it be cool if they organized a community hair drive to help kids in who lost their hair to alopecia or leukemia?! We've seen teachers do incredible things on top of our lessons -- community service projects, for instance -- and supporting that was something we also had in mind when deciding which lessons to prioritize.)

Access to the Old Lessons
As a legacy Mathalicious user, you will continue to have access to those old Mathalicious lessons until the end of your current billing period as of the date we launched Citizen Math. All retired lessons will come down by June 1, 2022 at the latest; but your access only goes until the end of your Mathalicious license.

Examples of when your access to old Mathalicious lessons will end depending on the expiration date of your Mathalicious account when we launched Citizen Math:

  • Expiration date between April 1, 2021 and June 1, 2022: If you had a one year license on Mathalicious that expires in August 2021, then you'll have access to those old Mathalicious lessons (via Citizen Math) through August 2021. When that expires, you'll be prompted to sign up for a new Citizen Math plan/subscription, and you will no longer have access to the old lessons.

  • Expired before April 1, 2021: If your Mathalicious account expired before the launch of Citizen Math, then you will not have access to the old Mathalicious lessons.

  • Expires after June 2022: If your Mathalicious account somehow has an expiration date past June 1, 2022, you will have access to the legacy lessons until June 1, 2022 at which point the lessons themselves will just be removed from the site entirely.

  • Monthly Users: If you're on a recurring Stripe subscription from Mathalicious, you'll have access to the old Mathalicious lessons until June 1, 2022 as long as your subscription stays active and does not change. If you have a Paypal subscription from Mathalicious, you need to switch to Stripe. Email us.

As always, we want to support teachers in having a great classroom experience. Please email us at if you'd like help finding a replacement lesson, or if you were one of the few folks who taught a special course with a Mathalicious lesson a week and this cramps your style. We'd love to chat.

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