Make Liars of Your Students

Today’s Contributor: Shane Rosenkrantz, Math Teacher & CIC at Reagan ECHS

Say you’re me and you’ve been following Dan Meyer’s work since you first became a math teacher. Of course, since you’re me, you’re a big fan of using Desmos in the math classroom for many reasons, including their ever-evolving classroom activities functionality.

Honestly, even before Desmos activities, you used it to spice up some of your lessons with home-grown animations like this one to help demonstrate how tracking the height of a single point on the edge of a waterwheel as it rotates gives us a periodic function. (Shout out to all the Precal teachers out there!)

Well, if that’s the case, you definitely saw the dy/dan blog post “Desmos + Two Truths and a Lie” and were enamored with the thought of your students challenging each other’s claims with evidence.

Even more amazing is the fact that you, Shane Rosenkrantz, Math Teacher and CIC at Reagan ECHS, created a similar experience for your Calculus students using BLEND’s discussion feature a whole two months earlier!

The rules were simple:

  • Reply with a top-level comment containing two true statements and one false statement.
  • Respond to at least two other students using evidence to refute the false statement.

Of course, as with anything that winds up feeling a bit magical in the classroom, there were are a few unwritten rules as well:

  • Some students wrote their three statements quickly and were able to move on to the next phase of the lesson, while others needed help constructing their arguments. By checking in on the discussion myself, I was able to quickly see who needed that extra push.
  • There was value in “breaking” the rules. When students wrote more than one false statement, the discussion became more interesting, not less.

This activity took about 5 minutes of whole-class time to launch and allowed my students to participate in a think-write-share mode with the added benefit of asynchronous discussion. By having everything exist on a discussion board, they could revisit their posts and respond to new insights, even correcting their original statements for increased clarity.

The best part is that the activity and feedback loop it created could be redone with any content in which students are expected to use evidence to support a claim. Whether that be textual evidence (What did the author say ELA?), experimental evidence (enjoy the debate about whether or not that’s silver nitrate!), or historical evidence (I’ve run out of clever things!).

Creating a discussion in BLEND is no more difficult than creating an Assignment, but there are a few settings you’ll need to understand before you push it live to your students.

  • Checking “Allow threaded replies” will ensure that students can respond to one another without having to create a top-level comment.
  • “Users must post before seeing replies” deserves some thought on your part. Do you want students who are having trouble to be able to see their peers’ responses before constructing their own response?
  • “Allow liking” was important for this discussion since I wanted students to “like” the replies that chose the false statement with applicable evidence.
    • “Sort by likes” will allow replies with many likes to be filtered to the top of a post. If you want your discussion to involve some basic “voting,” this can be helpful.

As with any digital vs. face-to-face choice we have to make as teachers, be sure to weigh the benefits honestly and remember not to get overtaken by just how cool all this stuff is! I chose to make this discussion digital to ensure my students’ thoughts could be recorded and shared in the classroom without taking 20 minutes to do a full class share out and debate. Truths and lies that were more interesting naturally exploded into face-to-face conversations, so I think we got the best of both worlds.


  1. Wish there were a LOVE button for this! The idea of using discussions to have students present and debate evidence is awesome, and turning it into a two-truths-and-a-lie game makes the thinking even better. This could be adapted for even really basic STAAR prep, too–students having to justify and convince others of their answers. So inspired!

    1. Thanks for the kind words!

      I know for my math classes, the next step would be having my students create their own graph/figure to embed in their top-level comment along with their statements. That extra element of student creation would get us a bit closer to what Dan Meyer’s getting at with the Desmos version of the activity.

      Your mention of STAAR prep reminds me of an activity framework shown off at lead4ward’s Rockin’ Review called “Make the Case” in which students break into “law firms” to prosecute their answer choice “clients.”

      — Shane

  2. Thanks for sharing such a powerful example. I love your last paragraph regarding the importance of thoughtfully making design decisions versus getting caught up in tech for tech’s sake. That thoughtfulness supports authenticity for the students.

  3. Whoa… I am blown away – this is great! I love the two truths and a lie structure. I never would have thought of putting it into BLEND. As a matter of fact I think I will try this today. Thank you!

  4. You are truly a mathematical rock star as well as a blended learning genius! Thank you for sharing this awesome example!

Leave a Reply