1. Greatest Common Factor Objective: Finding Greatest Common Factor (GCF) VocabularyThe greatest common factor is the biggest factor that is common to two or more numbers.

2. Method 1: Listing the Factors Find the GCF of 24 and 40 24 1 212 38 46 40 1 220 410 58 What’s the biggest common factor? The GCF of 24 and 40 is 8.

3. Method 2: Using Prime Factorization; “Upside-Down division ” Find the GCF of 45 and 60 45: 335 The common prime factors are 35; The GCF is 15 45 60: 2235 3 153 5 2 302 15 60 3 5

4. Method 3: Using Prime Factorization; Factor Trees Find the GCF of 36 and 48 36: 2233 The common prime factors are 223; The GCF is 12 36 6 2 3 48 6 8 2 3 2 4 2 48: 22223