Procedure: Find the Greatest Common Factor (GCF) by Listing
Procedure: Find the Greatest Common Factor (GCF) by Listing teaches Grade 6 students to find the GCF of two numbers by listing all factors of each number, identifying the common factors, and selecting the largest one. Covered in Illustrative Mathematics Grade 6, Unit 7: Rational Numbers, the GCF is essential for simplifying fractions, factoring expressions, and solving real-world grouping problems. This listing method is reliable and appropriate for smaller numbers before more efficient methods are introduced.
Key Concepts
The greatest common factor (GCF) of two numbers is the largest number that is a factor of both numbers.
Common Questions
How do you find the GCF by listing factors?
List all factors of each number. Find the factors that appear in both lists. The largest of these common factors is the GCF.
What is the GCF of 12 and 18?
Factors of 12: 1, 2, 3, 4, 6, 12. Factors of 18: 1, 2, 3, 6, 9, 18. Common factors: 1, 2, 3, 6. The GCF is 6.
What is the GCF used for?
The GCF is used to simplify fractions (divide numerator and denominator by their GCF), factor expressions, and solve problems about splitting items into equal groups.
Where is finding the GCF by listing in Illustrative Mathematics Grade 6?
This procedure is in Unit 7: Rational Numbers of Illustrative Mathematics Grade 6.
What is the difference between GCF and LCM?
GCF is the largest number that divides both numbers evenly. LCM (Least Common Multiple) is the smallest number that both numbers divide into evenly.