To write a program that finds all prime numbers less than or equal to a user-supplied integer N, the approach involves checking divisibility only by prime numbers up to the square root of N. For example, with N=60, the process starts by identifying all integers from 2 to 60 and checking each for primality. A function can be implemented to determine if a number is prime by testing divisibility against known primes less than or equal to the square root of that number. This reduces unnecessary calculations and optimizes the process. Additionally, a function to check if a division results in an integer can be useful for confirming non-primality. This method effectively streamlines the identification of prime numbers through efficient checks and calculations.
