Enjoy any 5 free lessons!
You can pick. No account needed.
Watch Video

You have remaining on your free trial.
4 Free Lessons Left
Get unlimited access to all videos and lesson plans with a membership.
So you can keep watching more great videos in class, ask your teacher or principal to get a School plan membership.
Become a member to get full access to our entire library of learning videos, reading material, quiz games, simple DIY activities & more.
Become a member to get full access to our entire library of learning videos, quiz games, & more.
Plans & Pricing
to watch this full video.

Access All Videos
and Lessons, No Limits.
Access All Videos

No credit card required,
takes 7 sec to signup.
No card required

Ready-to-go lessons
that save you time.
Ready-to-go lessons
If you are on a school computer or network, ask your tech person to whitelist these URLs:
*.wistia.com, fast.wistia.com, fast.wistia.net, embedwistia-a.akamaihd.net
Sometimes a simple refresh solves this issue. If you need further help, contact us.
Greatest Common Factor & Least Common Multiple

- Show lesson plan & teacher guide
- Show answers to discussion questions
- Show video only
- Allow visiting of other pages
- Hide assessments
- We'll learn how to find the Greatest Common Factor.
- We'll also learn how to find the Least Common Multiple.
- And we'll see how this knowledge can help us plan a barbecue, play sports, and even race cars!
-
Discussion Questions
- Before VideoWhat is a factor?ANSWER
A factor of a number is a whole number that, when multiplied by another whole number, equals the original number. For example, 4 and 2 are factors of 8 because 4 × 2 = 8.
10: 1, 2, 5, 10. 8: 1, 2, 4, 8. 2 is a common factor.
A multiple of a number, n, is a number that I can find by multiplying n by a whole number.
4: 4, 8, 12, 16, 20, 24, …; 6: 6, 12, 18, 24, 30, 36, …; both lists have 12 and 24.
I could color in squares on a number chart. I count skip count on a number line.
- After VideoWhat is a greatest common factor (GCF)?ANSWER
The GCF of two numbers is the greatest number that is a factor of both numbers.
Yes, two numbers may have no factors in common except 1, like 2 and 3.
The LCM of two numbers is the least number that is a multiple of both numbers.
When I look at the two lists of multiples, the LCM is the first number that the lists have in common.
I can look for key division words for GCF, such as "split evenly" or "equal groups" and size words like "greatest" and "maximum." For LCM, I can look for key multiplication words like "repeatedly" and size words like "least" and "minimum."
-
Vocabulary
- Factor DEFINE
A factor of a number, n, is a whole number that, when multiplied by another whole number, equals n.
- Factor pair DEFINE
A factor pair of a number is a pair of factors whose product equals the number.
- Multiple DEFINE
A multiple of a number n is a number that can be found as a product of n and another whole number.
- Common factor DEFINE
A common factor of a set of numbers is a number that is a factor of every number in the set.
- Common multiple DEFINE
A common multiple of a set of numbers is a number that is a multiple of every number in the set.
- Greatest common factor DEFINE
The greatest common factor of a set of numbers is the greatest number that is a factor of all numbers in the set.
- Least common multiple DEFINE
The least common multiple of a set of numbers is the least number that is a multiple of all numbers in the set.
- Factor DEFINE
-
Reading Material
-
Practice Word Problems
-
Practice Number Problems
-
Lesson Plan
-
Teacher Guide