Loading
Proofs and combinatorics for people who like clean edges.
the shape of this subject
Discrete math builds the muscle for CS proofs, cryptography, and algorithm analysis. Brainback insists on writing the base case yourself.
Because discrete math rewards the students who do the reps — and punishes the ones who outsource them.
Add Discrete math as a Learn subject and every problem in these areas routes to the Socratic tutor — attempt-first, hint-laddered, output-guarded.
Attempt → correction → guiding question. No answer. Ever. Verbatim from a beta session.
Base case n=1 gives 1 = 1(1+1)/2 = 1. Assume true for k…
Prove by induction: what's the base case? What's the inductive step?
no answer · one guiding question · your next move
the anti-pattern
Answer machines make discrete math look like a solved problem. It isn't. The exam room reveals whose reasoning was built and whose was rented.
the recall card
Every wrong attempt and low-scored explain-back becomes a card. SM-2 schedules them — the tricky ones come back tomorrow, the solid ones drift out to next week, then next month.
Recall the core concept in your own words. Then apply it to a fresh example under 2 minutes.
The subject where the shortcut has always been most expensive.
Limits, rates, and shapes of change — earned, not delivered.
Where symbolic manipulation becomes second nature — or doesn't.
See the diagram. Not just look at it.
Unit circle, but also unit intuition.
Vectors are directions, not numbers.
→discrete math — ready when you are
Attempt-first. Never the answer. Add it as a Learn subject in 30 seconds.