Big ideas about equality for little kids

This week I was working with a small group of first and second graders who are having a hard time with this grade 1 Common Core Standard around equality.

CCSS.Math.Content.1.OA.D.7 Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true and which are false? 6 = 6, 7 = 8 – 1, 5 + 2 = 2 + 5, 4 + 1 = 5 + 2.

They are also having a difficult time with addition and subtraction facts so that is what I decided to tackle first.  We were working on fluency of addition facts using a dice game and our 10 bead sticks when the opportunity to work on this idea about equality presented itself.

A pair of students had just rolled a 9 and an 8 and were talking with each other about how they found their answer using the 10 bead sticks to help explain their thinking.

The student whose sticks are in the top of this picture said, "I put 9 on one stick and 8 on the other but then I took one from the 8 stick and gave it to the 9 stick and made it 10 and 7."  I asked this student if he thought 10 and 7 was the same as 8 and 9 and he said yes.

His partner then said that she showed 9 on one stick and 8 on the other and said he saw 8+8+1.  I asked him if he thought that was the same as 9+8 and he said yes.

Here is where I stopped the whole group and had these two students share what they had noticed.  I recorded their ideas as equations on the board.

We talked about one equation at a time and kids shared ideas about whether or not they thought the equation was true and how they could prove it.  There were some kids who were not convinced that these equations were true, so I pulled out my math balance and the kids who thought the equations were true used it to convince the other kids that they were right.

The left side is showing 9 + 8 and the right side is showing 8 + 8 +1 the  bar is parallel to the table which means the equations are equal

After discussing the equations 9 + 8 = 8 + 8 + 1 and 9 + 8 = 10 + 7 a student pointed out that we could write 17 = 9 + 8 so we added that to our list of true equations.

The students got back to playing their game and several times I had groups notice something similar about equivalent expressions and add their equations to the board.

Next time I take this group, we will continue talking about the ideas of equality as well as addition and subtraction facts with my Frog and Flower Equality game.

How do you make sure your students understand equality?

I chose the math literature book Equal Shmequal to follow up this lesson.  Click here to read more about it!

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