Note: The Common Core doesn't mention prime factorization! What a blunder!
Students find the prime factorization of certain whole numbers. They'll start with problems where the number is easy to factorize, either because the number is small, or because the number consists of mostly small primes. Then they'll progress to numbers which are larger or consist of larger prime factors. Some numbers are really difficult to factorize, and for these we'll learn how to use a computer to do the meticulous work for us. Next, give your students this challenge. After that, lead this investigation. Conclude by leading this one. Watch this to learn how.