Math & Number TheoryThe maths that keeps coming up
This is not number theory for its own sake — it is the few tools that algorithm problems keep needing: greatest common divisor, prime sieves, modular arithmetic and fast exponentiation, and counting. They show up again and again in cryptography, hashing and counting problems.
Why learn Math & Number Theory
Where it shows upPublic-key encryption runs on large primes and modular arithmetic: generating primes, computing modular inverses, doing modular exponentiation. Every lesson here is one of its parts.
→ Lesson: Modular Arithmetic1920×1080 is 16:9 because of the greatest common divisor. Fraction arithmetic, aligning periods and gear ratios are the same tool.
→ Lesson: GCD & LCMHow many paths from corner to corner, how many five-card hands. Binomial coefficients are everywhere in counting and probability — just watch for overflow and remember to take the modulus.
→ Lesson: Combinatorics