Greatest Common Factor and Least Common Multiple

Greatest Common Factor and Least Common Multiple

_{I can find the greatest common factor or least common multiple of two numbers.}

Multiple Select

Choose all the factors of 9

• 1

• 2

• 3

• 6

• 9

Multiple Choice

Which number is a factor of 10

• 3
• 4
• 5
• 8

Multiple Choice

Find ALL FACTORS of 24

• 1, 2, 12, 24

• 1, 2, 8, 24

• 1, 2, 3, 4, 5, 6, 8, 12, 24

• 1, 2, 3, 4, 6, 8, 12, 24

Multiple Choice

When we skip count, we are listing .....

• factors
• divisors 
• addition 
• multiples

Multiple Choice

List the first 5 MULTIPLES of 3

• 3, 6 10, 15, 20

• 1, 3, 2, 6, 4

• 3, 6, 9, 12, 15

• 6, 9, 12, 15, 18

Multiple Choice

Joe has listed the first 4 multiples of 7 as: 
7   14    22     28
Which one is incorrect?

• 7
• 14
• 22
• 28

Finding GCF Review

• 1st - Start by listing the factors of each number

• 2nd - Compare lists and circle any number on both lists

• 3rd - Find the largest circled number, that is the GCF!

Fill in the Blanks

What is the Greatest Common Factor of 15 & 27 ?

Fill in the Blanks

What is the Greatest Common Factor of 12 & 24 ?

Fill in the Blanks

What is the Greatest Common Factor of 18 & 30?

Fill in the Blanks

What is the Greatest Common Factor of 20 & 56?

Fill in the Blanks

What is the Greatest Common Factor of 45 & 54?

Finding Least Common Multiple

• Remember! Multiples are just skip counting by a number. They should start with the number itself.

• 1st - List the first 5-10 multiples of each number and compare lists

• 2nd - If you have found a shared number, stop. If you haven't continue until you do.

Fill in the Blanks

What is the Least Common Multiple

of 4 & 5?

Fill in the Blanks

What is the Least Common Multiple

of 6 & 10?

Fill in the Blanks

What is the Least Common Multiple

of 4 & 15?

Fill in the Blanks

What is the Least Common Multiple

of 12 & 16?

Fill in the Blanks

What is the Least Common Multiple

of 6 & 27?

GCF and LCM Word Problems

How do we know which to do?

Multiple Choice

At Kentucky Fried Chicken, the kitchen staff baked 96 chicken legs and 144 thighs.  The staff had to prepare platters for an office lunch.  If each platter will have the same number of legs and thighs, what is the greatest number of platters they can make?

• 48
• 2
• 4
• 16

Multiple Choice

Jeremy has two pieces of wood: one is 90 inches and the other is 72 inches. He wants to cut both pieces of wood into smaller pieces so that all these pieces are the same length. If he wants the pieces to be as long as possible and doesn’t want to have any lumber left over, how long should each piece be? How many total pieces of lumber will he have?

• Greatest Common Factor
• Least Common Multiple

Multiple Choice

The school cafeteria serves tacos every sixth day and cheeseburgers every eight day. If tacos and cheeseburgers are both on today’s menu, how many days will it be before they are both on the menu again?

• 14 days
• 24 days
• 34 days
• 44 days

Multiple Choice

A radio station is giving away a $100 bill to every 30th caller and movie tickets to every 40th caller.  Which caller will be the first to win both prizes?

• 5
• 2
• 10
• 120

Multiple Choice

At the movie theater, they give out a free drink to every 75th customer and a free bag of popcorn to every 30th customer. Who is the first customer that is going to win both free items?

• 16th customer
• 150th customer
• 300th customer
• 180th customer

Multiple Choice

Maya had 16 red flowers and 24 yellow flowers.  She wants to make bouquets with the same number of each color flower in each bouquet.  What is the greatest number of bouquets that she can make?

• 4
• 2
• 48
• 8

Multiple Choice

Eason is making activity baskets to donate to charity.  She has 12 coloring books and 36 crayons.  What is the greatest number of baskets she can make if each type of toy is equally distributed among the baskets?

• 2
• 12
• 36
• 6