Posted by Nicholas James 🥉
4 months ago

Note-taking for math-heavy lectures

If the professor moves fast through proofs and examples, what's the most effective way to capture the steps without writing every symbol? Looking for a simple approach I can stick with all semester.

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Hayden Petrov avatar
Hayden Petrov 94 rep
4 months ago
Top Answer

Use a structure-first template so you capture the logic, not every symbol. At the top of each new proof write Given:, Goal:, Strategy: in the margin, then number the major steps as 1, 2, 3 as the prof moves. In each step write a short trigger and result, for example "use Cauchy-Schwarz -> bound on norm" or "by induction step, P(k) -> P(k+1)", and skip algebra with a placeholder like [alg -> Eq. (3)]. Assign your own equation tags (1), (2), (3) to the board's key lines so your steps refer to them rather than re-copying and and circle the pivot line where the proof turns, like when existence becomes uniqueness. Keep a two-column page: left column holds the roadmap steps and equation tags, right column is empty during class for details you fill in later.

While the prof talks, aim to capture the flow verbs and reasons: define, assume, apply theorem X, substitute, conclude, and put a small square beside gaps you need to re-derive. Immediately after class, spend 15 minutes filling the squares, expanding one skipped algebra chunk per step and checking that each arrow you wrote is valid. Use consistent shorthand to stay fast, for example "wlog" for without loss of generality, "iff" for if and only if, and "dfn" for definition, plus one color for your paraphrase and another for questions. Concrete example: when they prove the derivative of x^x, you can write Given: y = x^x, Goal: y' = ?, Strategy: log-diff. Steps: (1) ln y = x ln x, [alg], (2) y'/y = ln x + 1, (3) y' = x^x(ln x + 1), and fill the [alg] later. If photos or recordings are allowed, grab a photo at each board reset and use it only to fill your right column, but the core method works with paper only.

Claudia Edwards avatar
3 months ago

Stop chasing symbols. Capture structure. I keep a narrow left column for the why tag and write the goal, then the named moves the professor says, like substitution, induction step, or by Cauchy. In the main area I sketch the chain with arrows and leave triangles where the algebra is dense, then fill those within a day. I use a second color only for results and definitions so scanning is fast. Stars mark confusion and get resolved during office hours or from the book that same night.

Co-sign the structure-first approach but then preload a tiny shorthand legend so your tags are lightning-fast (wlog iff, by def, cont, C-S, MVT), and number the pivot lines so you can reference them when you fill the triangles which, yeah... i also leave a two-line buffer after any dense algebra and add a quick end-of-page recap: statement, proof method, key lemmas used.

Liam Nguyen avatar
Liam Nguyen 29 rep
4 months ago

Trying to transcribe every squiggle is how you lose the plot. Treat the proof like logging an incident: write the goal, the givens, the tool used, then the result arrow. When the prof says by XYZ, that is the only phrase you write verbatim, and you draw a big box around the final line. If recording is allowed, run a voice memo and jot tiny time stamps on the page so you can jump back. Trust me, I have watched people try to screenshot RAM, and this beats that chaos.

Alyssa Thompson avatar
3 months ago

Write the aim at the top and then chain the big steps with arrows and theorem names. Leave blanks for heavy algebra and fill them the same day. Ten minutes of cleanup beats an hour later. You got this.

Try a two-column page: left for the flow (aim theorem names and arrows), right for gaps or algebra to fill the same day. Build a tiny shorthand for quantifiers, implications, and common operations so you can keep up without every symbol. Number the big steps so you can insert missing lines later without rewriting. I also star any leap that uses a definition or earlier result so I know what to review first.

Catherine Allen avatar
Catherine Allen 🥉 285 rep
3 months ago

Forget complicated systems & just paraphrase the steps in your own words with key equations highlighted. You'll retain more and it's super easy to review. This approach changed my math game for the better!

Donald Gray avatar
Donald Gray 🥉 126 rep
3 months ago

All these so-called effective methods sound great until the prof switches gears mid-lecture and you're left scrambling. I tried abbreviating once and ended up with notes that made no sense a week later. It's frustrating how fast they go and like they forget we're not all geniuses. Complaining aside, maybe record the audio and note timestamps for tricky parts. But good luck sticking with any system when the workload piles up. I doubt it'll be simple all semester.

Liam Nguyen avatar
Liam Nguyen 🥉 162 rep
4 months ago

Everyone loves fancy systems until the first chalk speedrun. You will not win by buying a tablet or inventing a new shorthand every week. Grab the theorem name, the one identity or definition that unlocks the step, and a tiny note for why it is legal, then move on. Everything else is noise while the train is moving. Right after class, spend twenty minutes with the textbook or a buddy repairing the gaps, because if you wait until tomorrow it is gone.

Noel Lefevre avatar
Noel Lefevre 🥉 211 rep
3 months ago

I have this routine where I sketch the main structure of the proof first. Then I jot down key steps with abbreviations for symbols. It keeps me from getting overwhelmed. I use colors for different parts like assumptions in blue. That way I can review later without the full mess. Works for my ADHD brain.

I use a two-column setup: narrow left margin for tags like Setup, Claim, Tool and Check, main column for the keywords of each step with step numbers and a quick arrow to what it depends on. Keep a tiny legend of 8–10 abbreviations you’ll reuse all semester, and circle pivot moves (like “apply IVT” or “expand by linearity”) instead of the algebra. If you miss a manipulation, leave a small blank with a box symbol and do a 5‑minute “fill the boxes” pass right after class to lock it in.

Jin Dubois avatar
Jin Dubois 🥉 128 rep
3 months ago

Right, i've seen students try every gadget under the sun, only to end up with a notebook full of scribbles that look like alien code. Here's a tip: focus on the logic flow, not every symbol. Write the theorem statement, then bullet the major leaps with quick notes like 'by induction' or 'contradiction here.' Add your own examples later to fill gaps. It's hilarious how many think recording the lecture is the fix, but then they never watch it. Trust me, active noting beats passive recording every time.

Quick note - One tweak that helps is a two-pass system: in class write the theorem, the goal, and a numbered spine of steps with brief justifications, leaving wide gaps. Right after class, spend 10 minutes expanding those gaps while it’s fresh, using the book to fill any holes. If you make a tiny personal shorthand list (⇒, ∴, WLOG, IH, def exp.), you’ll keep up without trying to copy every symbol.

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