OBJ: to find the greatest common factor of two or more

numbers.

Common Factor – a whole number that is a factor of two or more nonzero whole numbers.

Greatest Common Factor – the greatest of all common factors.

Relatively Prime – two or more numbers that have a greatest common factor of 1.

Method 1•List all the factors

of each number. Identify the greatest number that is on every list.

Method 2•Write the prime

factorization of each number. The GCF is the product of the common prime factors.

1. 12 and 302. 21 and 423. 16, 42, and 404. 27, 45, 905. 18 and 336. 39 and 507. 110 and 778. 21 and 160

Factor each monomial and find the common factors.

1. 6x and 15x2. 20x2 and 36x3. 32y2 and 6x2y4. 7xy3 and 28xy2

In class, Text p. 179, #’s 12, 14, 24, 25, 30, 31, 38, 42, and 44

HW – Complete Practice W.S. 4.2 all problems.