Discretica
The discrete math app that gets CS students through the course
Discretica pairs interactive calculators with proof practice and 500+ guided problems — from truth tables to graph theory — and it all works offline. No account. No ads.
Free to start · Optional Premium (weekly, yearly, or lifetime) · iOS 15.1+ and Android
What studying in Discretica looks like
Three more screens from the app: the seven-module topic map, a module opened up into its lessons, and a practice question answered.
Discrete math is where CS degrees get hard
Proofs don't work like calculus. Truth tables are tedious to check by hand. And most study apps cover algebra or calculus — not quantifiers, pigeonhole, or spanning trees. Discretica focuses on exactly the topics that show up in Discrete Structures homework, quizzes, midterms, and finals.
Check your work instantly
Build truth tables, evaluate set operations, and step through the Euclidean algorithm with tools that show how the answer is reached — not just the result.
Learn to actually write proofs
The Proof Trainer uses fill-in-the-gap, reorder-the-proof, and choose-the-method exercises to build proof intuition one decision at a time.
Practice that sticks
Your mistakes go into a mistake notebook with spaced review, so the problems you got wrong come back until you can get them right.
Every core topic in the discrete math syllabus
Seven modules mapped to what Discrete Mathematics and Discrete Structures courses actually test.
Logic & propositions
Connectives, truth tables, logical equivalences, and quantifiers.
Proof methods
Direct proof, contradiction, contrapositive, and induction.
Sets, functions & relations
Set operations, Venn diagrams, properties, and mappings.
Counting & combinatorics
Permutations, combinations, pigeonhole, and the binomial theorem.
Graph theory & trees
Paths, cycles, connectivity, BFS, DFS, and spanning trees.
Boolean algebra
Expressions, laws, logic gates, simplification, and circuits.
Number theory
Divisibility, primes, modular arithmetic, GCD, LCM, and the Euclidean algorithm.
Seven interactive tools, built for homework
Each tool is designed around a specific kind of discrete math problem.
Truth Table Builder
Logical expressions with AND, OR, NOT, implication, biconditional, and XOR.
Set Operations
Union, intersection, difference, symmetric difference, cardinality, power sets, and Venn visuals.
Combinatorics Calculator
Permutations, combinations, factorials, and stars-and-bars.
Modular Arithmetic
Addition, subtraction, multiplication, powers, and inverses.
Base Converter
Binary, octal, decimal, and hexadecimal.
GCD & LCM Calculator
With Euclidean and extended Euclidean steps shown.
Proof Trainer
Fill-in-the-gap, reorder-the-proof, and choose-the-method exercises.
Practice that actually helps
- 500+ bundled problems across beginner, intermediate, and advanced levels — no connection needed.
- Hints, explanations, and step-by-step solutions so a wrong answer becomes a lesson, not a dead end.
- 30 rotating daily challenge problems to keep a little discrete math in every day.
- Mistake notebook with spaced review that resurfaces what you got wrong at the right time.
- Progress tracking with streaks, levels, topic mastery, and achievements.
- 54 formula and reference cards covering the core syllabus for quick pre-exam review.
- Offline by design — study on the bus, in a lecture hall, or anywhere without Wi‑Fi.
- Private by default — no account needed, no ads; progress stays on your device.
Free to start, upgrade if it earns it
Try the core of the app
- Four free calculators
- First subtopic in every module
- Daily challenge problems
- Up to 8 practice problems per day
Everything, unlocked
- All lessons and all tools
- Unlimited practice with step-by-step solutions
- Full mistake notebook and the Proof Trainer
- Weekly or yearly subscription — or lifetime access with a one-time purchase
Frequently asked questions
Yes, Discretica is free to download. The free tier includes four calculators, the first subtopic in every module, daily challenge problems, and up to 8 practice problems per day. Discretica Premium unlocks all lessons, all tools, unlimited practice, step-by-step solutions, the full mistake notebook, and the proof trainer via a weekly or yearly subscription, or a one-time lifetime purchase.
Yes. All 500+ practice problems are bundled with the app, so you can study offline — on a commute, in a library basement, or anywhere without a connection.
No account is needed and there are no ads. Your learning progress, preferences, and mistakes are stored on your device.
Seven core areas: logic and propositions; proof methods (direct, contradiction, contrapositive, induction); sets, functions, and relations; counting and combinatorics; graph theory and trees; Boolean algebra; and number theory including modular arithmetic and the Euclidean algorithm.
Discretica is built around the topics that appear in homework, quizzes, midterms, and finals for Discrete Structures and Discrete Mathematics courses. It includes 500+ problems across beginner, intermediate, and advanced levels, 30 rotating daily challenges, a mistake notebook with spaced review, and 54 formula and reference cards.
Yes. Practice problems come with hints, explanations, and step-by-step solutions, and the GCD/LCM calculator shows Euclidean and extended Euclidean steps. Full step-by-step solutions are part of Discretica Premium.
Yes. Discretica is a universal iOS app (iPhone and iPad, iOS 15.1 or later) and is also available on Android via Google Play.
Study guides
Free, evergreen explainers on the discrete math topics students search for most.
How to Study Discrete Math (Without Drowning)
Why discrete math feels different from calculus, and a week-by-week strategy for keeping up with proofs and problem sets.
Read the guide →Truth Tables Explained: From Connectives to Tautologies
How to build a truth table by hand, what implication really means, and how to spot tautologies and contradictions.
Read the guide →Proof Methods: Direct, Contrapositive, Contradiction & Induction
How to choose the right proof technique — with the tell-tale signs that a problem wants induction or contradiction.
Read the guide →Permutations vs Combinations: When Order Matters
The one question that untangles most counting problems, plus factorials, binomial coefficients, and stars-and-bars.
Read the guide →Modular Arithmetic Basics: Clock Math for CS Students
Congruences, remainders, GCD, and the Euclidean algorithm — and why they power hashing and cryptography.
Read the guide →