This Greatest Common Factor lesson will get students thinking about what it means to find the GCF of two numbers. This lesson provides a hands-on activity to finding the GCF using prime factorization. Students will use prime number cards to figure out the prime factorization of two numbers. Then, students will find the common factors of the two numbers and will multiply them to find the GCF. If you teach using factor trees to find GCF, this is the perfect concrete lesson.
The lesson suggests students working in groups but this activity would also work for independent work or work in pairs.