Clothesline Equations – A Family Math Night Activity
Back in August I signed up for a Thinking Summit put on by Christina Tondevold, founder of Build Math Minds. It was three days of amazing presenters sharing their expertise in K-8 math. One of the presenters, Kristen Acosta, mentioned she did an activity with her sixth graders that she called Clothesline Math. Hmmm…I thought. That’s a really cool idea. Wouldn’t it be fun to do something like that at a Family Math Night event? So that’s what I did.


Collaborative Clothesline Equations
I adapted the original idea of having only a number hanging on the clothesline to having students include a representation of the number. This came in the form of a picture for the kinders and an equation for grades 1-5. As much as I can, I like students to have a choice about part of the activity so for this one I let them choose the number they worked with.

The Activity Sheets
Just like most of our family engagement activities, I created Beginning (K/1), Intermediate (2/3), and Advanced (4/5) level Activity Sheets. I happened to be hosting a Gellin’ with Geometry event so I printed the sheets in yellow, green, and blue respectively to match the Gellin’ activities.
I’ve included the detailed PDF lesson FREE for you below.

I placed the appropriate Activity Sheets at each level and spread out the pencils and colored pens. I also included 0-110 charts at the Intermediate level and fraction circles at the Advanced level in case students needed them to help with their equations.

Math Goals
I had several goals for this activity. One was simply having students choose a number and then create an equation for that number. To make it slightly more challenging at the Intermediate and Advanced levels, I had the Intermediate level focus on even and odd numbers and the Advanced level focus on fractions and mixed numbers.
My second goal was to have students think about the placement of their number when they were placing it on the clothesline. I intentionally only allowed the Beginning Level to use the numbers 1-20. These little guys are still learning about numbers on a number line and I didn’t want to confuse their learning by having a fifth grader add a number like 2 1/4 in between the numbers 2 and 3.
I knew even before I did the activity that there would probably be a lot of shifting numbers once students started hanging their numbers. For example, if the numbers 45 and 46 were hanging next to each other and a student needed to add the number 45 1/2, it would be necessary to slide the numbers apart to make room for it. But that’s great and part of the learning.

Multiple Representations
Another goal was to have students see that numbers can be composed in different ways. To do this, I needed to figure out how to hang the repeat numbers to maintain an accurate number line. That’s when my assistant came to the rescue with the idea to use tape and hang repeat numbers off of each other vertically.
What I Learned and useful Tips
Over the many years of hosting Family Math Night events, I’ve learned that anytime there are colorful pens and scissors on the table, it’s going to be a busy station. And that’s exactly how this station unfolded. The sixth grade station facilitator in charge of this station was kept on her toes all evening.
One thing I did notice was the young kinders weren’t sure where to place their number on the clothesline. So next time I’m going to add a large 1-20 number path somewhere on the wall next to the left-hand side of the clothesline as a support tool in case the younger students need help placing their numbers.

Tip #1
So that families have a general idea of what’s going on with the clothesline, it’s a good idea to “seed” it with a few numbers. We used the numbers 5, 11 and 56 on our clothesline and placed them in the appropriate linear spot on the line. That gave students a starting point when figuring out where their number went.

Tip #2
Since it’s a clothesline, I thought it would be fun to add actual clothespins. I found some colorful ones on Amazon. The key here is to make sure participants hang their number “tent” on the clothesline BEFORE they add the clothespin. Hanging the tent first then adding the clothespin helps ensure that the number hangs correctly.

Tip #3
Sometimes a child works sooo hard on their project that they completely fall in love with it and don’t want to let it go. That’s exactly what happened with this little guy. He came up to me and asked if he could keep his equation instead of adding it to the collaborative number line. And of course, when that happens, they’re welcome to take their piece home and share it.
Clothesline Equations in Action








If you’re looking for a super simple and super fun activity at your next Family Math Night event, Clothesline Equations is a fabulous one! For more fun collaborative projects, check out our Resources page. And if you’re interested in hosting a super fun Family Math Night event and have questions, feel free to reach out!