Do you use the ladder method in middle school or elementary math, to find GCF, LCM, or for any other math concepts?
If you haven't had the chance to use the ladder method (or the upside down birthday cake method, as some call it), I highly recommend it.
Uses of the Ladder Method
As you can see in the anchor chart (sorry it's not as pretty as some!), math students can use the ladder method for greatest common factor (GCF), least common multiple (LCM), factoring, reducing fractions, finding prime factorization, and for finding the least common denominator (not pictured)! So many uses!
Benefits of Using the Ladder Method
1) What I really love about this method is that the process is the same for each use; the outside numbers are just used differently. I love the fact that the continued use of the ladder method (for various math concepts) leads middle school math students to make greater connections between numbers.....and finding factors seems to come more easily.
2) In addition to helping math students find GCF and LCM, using the ladder method helps students see the relationships between numbers more clearly. It's very easy to see what factors the numbers have in common and how those factors 'contribute' to the LCM or GCF.
Ladder Method for Factoring
When I started using the ladder method for factoring, students picked up the factoring concept MUCH more quickly than when I hadn't used it.
The steps to use the ladder method for factoring are:
1) Put the expression into the ladder.
2) Take out the common factors, one at a time (common factors go outside the ladder, then divide each number in the expression by that factor and put the quotient below the numbers in the ladder. Repeat until all common factors have been 'removed.')
3) Multiply the numbers on the left of the ladder - these are the GCF and go outside the parenthesis in the factored expression.
4) Put the numbers at the bottom of the ladder into the parenthesis.
The short video below demonstrates how to factor a simple expression.
Ladder Method Resources
A while back, I wrote a guest post about the ladder method on Rachel Lynette's blog, so if you're interested in reading more, check it out here. I shared a ladder method fold-it-up in my guest post, but you can also click on the image here, if you'd like to download it.
I've also created a fun Doodle Notes page to help students with the Ladder Method!
Click on the image, to see it on TPT.
If you haven't used the ladder method before, I hope you'll give it a try! If you have, I'm sure you understand why I love it:-)
To read next: