One thing that I have discovered over the years is that students can be very trained to "fill in the box". The more focus we put on our math series and workbooks, the more true this is. In my mind, it is our obligation as elementary math teachers to develop mathematical thinking in our classrooms--and there are so many ways to nurture this...providing students with many rigorous problem solving opportunities, having in-depth mathematical discussions, doing number talks, providing many different experiences to build numbers sense--and developing algebra thinking in our students.

What? Algebra? YES.

In a nutshell, algebra is the area of math that deals with mathematical symbols and the rules that exist for using them. As students get more sophisticated with their thinking, of course these symbols and rules get more complex. For me, one of the key symbols we can address in the intermediate grades is the equal sign.

The
concepts of “equals” is such an essential mathematical concept—and one that is
often not taught explicitly in many math programs. Consider the following problem:

7 + 5
= ___ + 3

Students
have a good sense of the concept of equals know that “9” goes in the box. Every year, I am shocked by the number of
students who think it is “12”—or that the problem can’t be done at all! Many students are programmed to think that
the “=“ sign means “find the answer” when, in actuality, it is a sign
indicating that the two sides balance.
Deep understanding of this helps down the road with algebra and other
more advanced math—and also makes a smooth transition to INequalities as well.
Moving our “box” (or “variable”, or a letter, or a line, or a question
mark) to different places in equations helps students think about numbers and
equality and not just filling in the blank. So--give it a try! See where your students are!

After we have a pretty in-depth discussion about this problem, we do a few more similar ones together and then I send my students off in pairs to try a BUNCH more--where they come up with the answer and must defend it by explaining the math. I want them using language like "In order to make the equation balance, both sides must be worth 13...the right side already is, and the left side needs 6 more to make 13." or something like that! I walk around and monitor and coach this. I really play this up...explain that they are doing ALGEBRA and they love it! I tell them that we can make these problems more and more challenging as the year goes on--and we do!

Because we are working with whole numbers right now, I continue to have my students working on this "concept of equals" with harder and harder problems. Some of my students are even ready for an enrichment group where we learn about order of operations so we can solve some really fun ones!

As the year progresses, we can even do similar problems with decimals, fractions, measurement concepts and more!

For some of my students, they need a little reinforcement with this. I met with a group to do more of the single digit cards where we broke out some manipulatives to model the balance. I have even pulled out a pan balance in the past to REALLY show this idea of "balance". Once they started getting more confidence, I used this "The Missing Piece" game to start to expand the concept to double digit numbers so students really see how "two parts" can make a "whole". Even my stronger students love this game because they start to make some predictions about numbers they "need"--it's fun to watch their growing mathematical thinking

So--I'd LOVE for you to give this a try with your students and then let me know how it goes! If you want a set of task cards that have a whole bunch of problems at 4 levels, just click the image below to see what I have been using with my students. Enjoy--and make sure to tell me what you find!

Interested in "The Missing Piece"? It's one of the five addition and subtraction games in this resource: