Lesson objective: Find the least common multiple and greatest common factor of two given numbers.

This lesson helps to build procedural skill with least common multiples and greatest common factors. Lists and prime factorization are used here because they support an organized way of thinking about how a number can be broken down. This work develops students' understanding that every factor of two given numbers is also a factor of every multiple of those two numbers.

Students engage in Mathematical Practice 2 (Reason abstractly and quantitatively) as they break numbers into factors to find the least common multiple and greatest common factor of two numbers.

**Key vocabulary:**

- factor
- greatest common factor
- least common multiple
- multiple
- prime factorization