Grade 6 · Math · Lesson 5

Least Common Multiple and Greatest Common Factor

When two numbers share factors and multiples, two special values stand out. The Least Common Multiple (LCM) is the smallest non-zero number both can divide into. The Greatest Common Factor (GCF) is the largest number that divides both evenly. LCM helps with adding fractions and scheduling repeated events; GCF helps with simplifying fractions and splitting groups fairly.

What this lesson teaches

1Find the least common multiple (LCM) of two whole numbers by listing multiples
2Find the greatest common factor (GCF) of two whole numbers by listing factors
3Use prime factorization to compute the LCM and GCF of larger pairs
4Apply LCM and GCF to solve simple real-world word problems

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