4 Reasons I Love Using Number Lines as a Strategy for Addition

My New Favorite Strategy for Addition: Using a Number Line to Add

One strategy for addition that I am seeing a lot of success with for students is adding with a number line. The last few years, our math sequence had us start with graphing, including having students find the difference between two different categories, in first grade. This was incredibly hard for students because we hadn’t even focused on what was probably the most crucial thing to ensure students can do in first grade: simple addition and subtraction. Thankfully, the district realized this order didn’t make sense and has this year changed our sequence to where we start with teaching addition and subtraction– and boy, has it already made a world of difference!

Students are taught many great strategies for addition in first grade– counting on, drawing a picture, doubles, doubles plus one, making a ten, and so on. There are several reasons I think teaching addition with a number line has been such an effective strategy for addition so far, especially for my students who don’t have great number sense.

Reason #1: The Numbers are Already Written Down

For my students who might not know what all the numbers look like or have trouble counting higher up on their own, a number line is a great tool to take some of that burden off of them. I love that on a number line all the numbers are displayed for students and it’s not something they have to remember or write down each time.

Reason #2: Students Don’t Have to Draw a Picture

While I think drawing a picture is a great strategy for addition, it’s not always the best for some students. First off, if they struggle to count to higher numbers on their own, I notice students losing track of how many circles they’ve drawn when using a picture. While I try to get my students to draw their dots organized like a ten frame, not all of them do that on their own, and some draw huge dots clumped together while others draw tiny dots. I have some students who draw such tiny dots that they won’t notice they need to count it when adding up their picture and end up getting the answer wrong.

With number lines, students don’t need to count and draw dots. They can simply draw their number line jumps using a dry erase marker and they only need to jump the amount of the smaller addend. This allows for less room for error, in my opinion.

Reason #3: Guides Can Help Students Know How to Add or Subtract

I love giving students name plates that have a number line on them. I created this name plate a few years ago to include the alphabet (so students see the capital and lowercase version of each letter side by side) and a number line. On the left side of the number line I put a – (minus) sign and on the right end of the number line I put a + (plus) sign. I tell students that if they aren’t sure which way to “hop” when adding of subtracting, look at which side the symbol they are using is and move that direction.

While this may seem like a simple guide, it has worked WONDERS this year for a few of my struggling adders, and it is crucial to their success. After using the number line over and over again, students should eventually be able to remember that “jumping” left on the number line means they are subtracting and “jumping” right means they are adding.

Reason #4: It’s Easy to Use Over and Over Again

This year we made number lines for each student (in addition to the one on their name plate). They are able to keep it in their desk and use it whenever they need to. The number lines were printed on white cardstock and then laminated for durability. Students can just grab a dry erase marker each time they want to use the number line and then erase after they are done solving each problem.

How I Teach Addition With a Number Line

1. I start by having students underline the bigger addend in the number sentence. If the question is on a piece of paper, they can simply underline the bigger addend on the paper. If we are practicing doing this as a class or in small group, I have students copy/write the number sentence on their desk with a box where the answer goes. Then, they underline the larger addend.
2. Students next have to also underline the larger addend on their number line. If we were doing 11+6, students would underline 11. This is where they will start. We underline the bigger addend so that they have less “hops” to do in later steps, which means less of a chance they mess up!
3. Students look at the smaller addend. They then make that many hops! (If your students struggle knowing which way to hop, be sure to point out the plus and minus sign on each end of the number line to serve as a reminder and guide for them).
4. After hopping, I have students circle the number they end up on. That is the answer, and they then write it in the answer box.

Just like with anything in life, this strategy for addition will take practice in order for some students to feel comfortable with it. I like to do a lot of practice problems on the desks with students (our desks are dry erase– you could also just use a dry erase board) so I can see who is grasping addition with a number line and who is not. I also pull students back to my small group table to practice even more in smaller groups or one on one.

Extra Practice with this Strategy for Addition

For more number line practice that provides instant feedback (without you having to be right there), be sure to check out my Counting on and Adding with a Number Line Boom Cards.

I designed this Boom Card deck to where students will drag the star to start at the big number. Next, they move the star however many “hops” they need to and wherever the star ends up is their answer. 

Number Line Freebie

If you think you might want to start using a number line to teach adding in the classroom, I’ve got you covered with a freebie below! Simply print, laminate, and cut for students to use over and over again!

Thanks for checking out this post! I hope you find this strategy for teaching addition using a number line to be helpful! I have given each of my students their own number line that they can pull out any time they need help with adding. It has proven to be such a helpful tool for addition that I hope your students can benefit from as well!

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