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