Monthly Archives: February 2021

Cold Temps, Thermometers and a Vertical Number Line


Sara’s tweet reminded me of my hand made thermometers my first years of teaching. Oh goodness. It has been a bit since I thought about them.

I printed, literally used a ruler and drew a vertical number line, labeling with integer values, made copies, cut them into strips. Since laminating was not as readily available 25 years ago, I used wide packing tape to laminate the strips.

Lame example, but you get the idea.

Next, I hole punched at the top and bottom of the number line. I tied together a piece of red yarn and white yarn. Threaded lose ends through each hole and tied it as tightly as possible in the back.

Students could slide the knot up or down depending on the representation or operation. Even today, I still keep a physical vertical number line up in my classroom and kids will tell you it helps them with those signed numbers.

To the right of the door…

Shortly after returning to the classroom in 2001, I created this number line with calendar number cards, adding negatives to half of them. It has followed me from room to room to room ever since.

Kids will sketch them in the margins of their notes. I have a template we tape into our INBs for at home use. I’ve never really dug into the why or looked for research of vertical vs. horizontal. I just observe with my students they are more confident in their work. I’m not sure how it helps or alleviates space with one of their memories. I just see it works.

Thanks for the reminder, Sara. I thought about that old classroom and wondered about several of those kids, who are now in or nearing their 40s. 😃