Trial Division is a straightforward method used to determine if a number is prime. It involves dividing the number by all integers up to its square root. If any of these divisions result in a whole number, the number is not prime; otherwise, it is prime. This technique is efficient for smaller numbers but becomes less practical for larger ones due to the increasing number of divisions required. More advanced algorithms, such as Sieve of Eratosthenes or Miller-Rabin primality test, are often used for larger numbers to improve efficiency in identifying prime numbers.