What Happens Before "Notice That"?
While reviewing for MATH 351, I reached a point where I was thoroughly fed up with the phrase “notice that” in mathematical proofs.
“Notice that we can choose ϵ=(L-a)/2.”
Looking at that choice, I knew it was positive, and I could follow the ensuing deduction to verify that it indeed worked. Yet I still wanted to ask: Why that specific choice? How did you come up with it? Why were you able to “notice” it, while I could only understand it after you wrote it down?
Back then, I felt the instructor’s observational power was simply superhuman.
Later, I gradually realized that—at least in these kinds of proofs—I needed to make a mental move I hadn’t been conscious of before: starting from the desired conclusion, working backward to find conditions sufficient to make it hold, and then returning to the hypotheses to verify that those conditions could be met. While a formal proof is written in a neat, forward-logical order, the actual process of discovery often involves pacing back and forth many times.
This realization brought immense relief. I finally understood that I could actively switch the direction of my thinking; I didn’t have to keep pushing blindly forward from the given premises, waiting for some magical choice to strike.
Immediately, though, another thought followed: What about the students who haven’t realized this yet?
If a learnable strategy is never explicitly articulated yet silently becomes a prerequisite for keeping up with the course, students who get stuck might have no idea what they are missing. They see someone else writing down a proof effortlessly, while they can’t even fathom the first step. In that vacuum, “I don’t yet know how to search for this proof” easily morphs into “Maybe I’m just not cut out for math.”
I cannot extrapolate why other students struggle based on my experience alone. But I have begun to wonder: do we sometimes rush to mistake unfamiliarity with hidden scratch work for a fundamental lack of ability?
My MATH 351 class used Inquiry-Based Learning (IBL). There is real value in letting students experiment, discuss, and discover mathematics for themselves. Nor do I want every problem pre-packaged into a mechanical checklist to execute blindly. Still, I wish classrooms left more room for the process of discovery itself: showcasing rough drafts, explaining failed attempts, or even saying outright, “Pushing forward from here, I’m stuck for the moment—so let’s see what the conclusion actually demands.”
Everything that happens before “notice that” is mathematics worth teaching, too.
Discussing this experience with AI helped me frame my confusion into a more concrete question: How much of an expert’s proof-search process is made visible in the classroom? This question isn’t unique to any single teaching pedagogy. Whether in a large lecture or small inquiry groups, students may still need guidance to understand how a particular choice was born.
This also sparked an idea for a small project: collecting concrete moments from different students in the classroom.
In which class, and at which step, did they start falling behind? When did their attention break? When did the thought “maybe I lack talent” first cross their mind? What later helped them grasp the concept anew, or gave them the resolve to keep trying?
These field notes might be scattered and fragmented. One person might stumble over notation; another might wonder why an auxiliary variable was suddenly constructed out of thin air; someone else might follow every individual step yet remain entirely lost about where the overall proof is heading. These fragments may not coalesce into a single, tidy pattern, and students’ reflections at the time might not pinpoint the true root cause of their difficulties.
Even so, I hope these glimpses can serve as a starting point for deeper understanding. By juxtaposing them with the course material, the instructor’s explanations, and the students’ subsequent learning trajectories, perhaps we can diagnose with greater precision: Where exactly did a student lose the thread, and what support do they need to reconnect it?
I am not yet sure if I have the time or resources to carry out this project. Right now, it is merely an idea that sprouted from the frustrations of exam review.
Yet it has already changed how I see learning obstacles. I want to ask: before a student decides they are “not smart enough,” has anyone helped them pinpoint the exact hurdle in front of them? Has anyone told them that the polished proof before their eyes might well be the product of hesitation, false starts, and repeated changes in direction?
I hope mathematics education can help more students demystify their struggles and find a way forward. And I would like to begin with the very moments that are so easily glossed over with a casual “notice that.”
This piece grew out of my reflections during MATH 351 review and a discussion with AI. The project described remains in the conceptual stage.


