How To Find the Greatest Common Factor
- December 4, 2009
- 1,269 Views
Writer
Randall Frost
Voice Over Artist
Nellesa Walthour
Music
Edison Music Corp
The methods for finding the greatest common factor for a series of numbers and for an algebraic expression are similar.
You Will Need
- A series of numbers
- Algebraic expressions
Step 1: Determine for a series of numbers
Factor each number in a series of numbers completely into its primes; identify the common factors for each number; and then multiply the common factors together.
A prime number is a positive integer that is not itself the product of two smaller positive integers.
Step 2: Use 18 and 27
Use the numbers 18 and 27 as an example. The primes of 18 are three, three, and two. The primes of 27 are three, three, and three. So the greatest common factor is three times three, or nine.
Step 3: Determine the greatest common factor for algebraic expressions
Identify all of the common factors in a series of algebraic expressions.
Step 4: factor 60x2y and 210xy2
Use the expressions the common factors of the first expression are two, two, three, five, x, x, and y. The common factors in the second expression are two, three, five, seven, x, y, and y. So the greatest common factor is two times three times five times x times y, or 30xy.
Did you know? The third century B.C.E. mathematician Euclid developed an algorithm for finding the greatest common factor of two natural numbers or two polynomials.
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Comments (1)
Seems to be a problem with Step 4. The step should begin with ";Use the expression 60x2y and 210xy2,"; with the exponentials properly shown (as superscripts).
over 2 years ago by Randall_Frost
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