4-2 GCF Greatest Common Factor (GCF) - The largest factor that is the same for a given set of numbers Two methods: 1.) Listing Method or modified listing method 2.) Prime Factorization and chart method Find the GCF of 40 and 140 using both methods.

40: 140: Listing method

Prime Factorization Method

Find the GCF of 12r3 and 8r Find the GCF of each set of monomials. Steps: 1.) Factor each monomial 2.) Set up the chart 3.) Multiply all common prime factors

Find the GCF of 36abc and 30a2c Find the GCF of 20x2, 36xy, and 28xy2

Relatively Prime- two numbers are relatively prime if their GCF is 1 Find the GCF of the numbers. Then tell whether the numbers are relatively prime. a.) 18 and 33 b.) 39 and 50

Demonstrate Understanding: Find the GCF of each. 1.) 48 and 32 2.) 200, 72 3.) 25x2y, 30x3y2 Find the GCF and tell if the numbers are relatively prime. 4.) 49, 91 5.) 16, 25