Divisors and Factors Section 2.3

Objectives Write a counting number as the product of two factors in all possible ways List all of the factors (divisors) of a counting number

Objective 1: Write a counting number as the product of two factors in all possible ways

Objective 1 Two numbers multiplied results in a product The product is a multiple of each number Each number is a factor of the result Each number is also a divisor of the result Can find factors of a number by: –Visualizing rectangles –Divide by every smaller number –Using the “square method”

Objective 1 The Square Method –List all the counting numbers from 1 to the first number whose square is larger than the given number –For each number on the list, test whether the number is a divisor of the given number –If the number is not a divisor, cross it off and all of its multiples off the list –If the number is a divisor, write the two factor pairs multiplied together

Objective 2: List all the factors (divisors) of a counting number

Objective 2 Use square method to find pair of factors of given number List all pairs of numbers in vertical form Read down the left column and up the right