Learning goals: Teacher Facing Comprehend (orally and in writing) the terms “factor,” “common factor,” and “greatest common factor.” Explain (orally and in writing) how to determine the greatest common factor of two whole numbers less than 100. List the factors of a number and identify common factors for two numbers in a real-world situation. Full lesson plan (warm-up, activities, synthesis, cool-down prompt) from 6.7 Rational Numbers, Grade 6.