Stage 37 · Beyond (Optional)

37.3.5 Working with Congruences and Their Uses

37.3 First Steps in Number Theory: Divisibility, Congruence, and Primes

Point 5 of 5

37.3.5 Working with Congruences and Their Uses

Core idea

Congruences can be added and multiplied, and modular arithmetic is handy for checking divisibility, figuring out the day of the week, or verifying a last digit.

Module goal. Starting from divisibility and remainders among the integers, meet the prime numbers as building blocks and congruence as a clock arithmetic, and feel the beauty of pure structure.

eastmath.com · 37.3 First Steps in Number Theory: Divisibility, Congruence, and Primes · 37.3.5 Working with Congruences and Their Uses