Eratosthenes

Eratosthenes was a Greek mathematician who is best known for developing a method to find all prime numbers up to a given limit, called the "Sieve of Eratosthenes." This algorithm works by systematically eliminating the multiples of each prime number, starting from 2. The numbers that remain are the primes. Additionally, he is famous for calculating the Earth's circumference with remarkable accuracy using observations of shadows in different locations. His work laid foundational concepts in mathematics and geography, demonstrating the power of systematic thinking and measurement.