My students “discovered” slope-intercept form in class last Friday through a paper-pencil graphing exploration that had just the right frustration level to get them talking, exploring, and revising until they “got it”. While we didn’t have a lot of time to come back together and formalize *y* = *mx* + *b* on Friday, I felt like they’d done enough to tackle Michael Fenton’s “Match My Line” today. Last year, my students accessed each Desmos graphing task from a ThingLink. This year, with the birth of Desmos Activity Builder, students tackled each challenge with a smoother living-in-Desmos work-flow.

Before we visited student.desmos.com, I gave a brief assessment using ThatQuiz to be sure we all remembered last Friday’s discoveries. Initially, I had planned to use “Match My Line” and then let students play a linear “Polygraph” activity… but we never got to the Polygraph.

Did you ever just wish another teacher was in the room with you to witness that this-is-actually-happening kind of lesson? That was today! After circulating with a goofy grin on my face for longer than I should have, I had the sense to grab a notepad and jot down some student comments I heard as they worked. I lost count of how many times students threw both hands up in the air as they said these, and many other comments, out loud:

**“See?!? I’m smart!”**

**“I didn’t know we could use decimals!”**

**“I GOT IT!!! I GOT IT!!!”**

**“… I missed it!”**

**“I’m almost done – I feel so smart right now.”**

**“Got it! Perfect!”**

**“OH! I did it wrong!”**

**“This is making me SO MAD… wait… BANG! GOT IT!”**

and my favorite… as the bell was ringing to dismiss for the day…

**“This should be our lesson every day.”**