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Rutgers
Computer Science
4 credits

Rutgers CS 205: Introduction to Discrete Structures I

CS 205 (01:198:205) is Rutgers' discrete math course for CS majors: logic, proofs, sets, functions, relations, and combinatorics. It's the theory backbone for later courses like algorithms, and it runs alongside the programming sequence.

Fennie is independent and not affiliated with Rutgers University. This is an unofficial study guide.

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What makes it hard

It's the first proof-based course most CS students take, and the shift from coding to constructing rigorous arguments is jarring. Induction proofs and counting problems are the usual exam killers — both look simple in lecture and fall apart on the page without lots of practice.

What you'll cover

  • Propositional and predicate logic
  • Proof techniques and induction
  • Sets, functions, and relations
  • Combinatorics and counting
  • Basic probability
  • Graphs

The CS 205 study guide

How to study for Rutgers CS 205, step by step.

  1. 1

    Write full proofs by hand, daily

    CS 205 is most students' first proof course, and the skill only builds through production. Twenty minutes of proof-writing a day beats a pre-exam marathon, every time.

  2. 2

    Compare your proofs to solutions line by line

    Not conclusion to conclusion — line by line. The gap between a proof that feels right and one that earns full credit is precision, and you learn to see it by auditing your own work.

  3. 3

    Categorize counting problems by technique

    Permutation, combination, stars and bars, inclusion-exclusion — keep a running list of solved problems sorted by method. Combinatorics exam questions are technique-recognition tests in disguise.

  4. 4

    Use recitation as your feedback loop

    Bring attempted proofs to recitation and ask the TA where the rigor leaks. Then redo every missed problem from scratch a few days later — that second pass is where it sticks.

  5. 5

    Make the reps automatic with Fennie

    Upload the CS 205 syllabus and Fennie's Daily Plan schedules proof and counting practice across the semester, paced to your exams, with practice problems generated from your actual course content. Free to start.

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How Fennie helps with CS 205

Daily Plans give CS 205 the steady proof-writing reps it demands — a little every day beats marathon sessions before exams. Chat through why an induction proof is incomplete or how to set up a counting argument, and generate practice problems for the techniques you keep missing.

FAQ

Is CS 205 hard at Rutgers?

It's a different kind of hard than the programming courses — proofs and counting instead of code. Students who practice writing proofs from scratch do fine; those who study by reading solutions usually don't.

When should I take CS 205?

Many students pair it with CS 112 or take it right after. It's a prerequisite for upper-level theory-leaning courses, so don't push it late in your plan.

How do I get better at CS 205 proofs?

Write full proofs by hand, compare against solutions line by line, and redo every miss a few days later. Combinatorics needs the same treatment — categorize problems by counting technique.

Pass CS 205 with a plan, not a cram

Upload your CS 205 materials and Fennie generates a Daily Plan paced to your deadline — plus chat, flashcards, and quizzes built from the actual course content.

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