This number sense lesson focuses on determining the prime factorization of numbers. The lesson includes research-based strategies and strategic questions that prepare students for assessments. In this lesson, students determine the prime factorization of the number using a factorization tree, factoring all composite numbers until they are prime. Finally, they write the prime factorization using exponents if necessary and checking and interpreting the answer. In addition to the lesson, there are twelve pages of Independent Practice and review with questions modeled after current adaptive testing items.