Grade 6 · Number
Factors, Multiples, GCF, and LCM
Factors and multiples are the architecture of the whole numbers. The prime numbers are the atoms: every composite number is built by multiplying primes. Finding the prime factorization of a number exposes its complete structure: 300 = 2^2 x 3 x 5^2. The GCF and LCM, computed from prime factorizations, are the tools needed for fraction arithmetic: to add 3/8 + 5/12, find the LCM of 8 and 12 (= 24) for the common denominator; to simplify 18/24, find the GCF of 18 and 24 (= 6).
LESSON VIDEO
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Lesson video
A short walkthrough to play in class or assign for flipped/at-home viewing.
WHAT STUDENTS WILL LEARN
✓Identify all factors of numbers to 100 using factor pairs
✓Classify numbers as prime or composite; determine prime factorization
✓Apply divisibility rules for 2, 3, 4, 5, 6, 9, and 10
✓Find the Greatest Common Factor (GCF) using factor lists or prime factorization
✓Find the Least Common Multiple (LCM) using multiples lists or prime factorization
✓Use Venn diagrams to compare numbers for common factors and multiples