Saturday, September 28, 2013

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!

You might also be interested in
Another lesson on equality
Penguin themed equality freebie
Frog and flower equality

15 comments:

  1. I'm impressed with the thinking they're doing here. Your beadsticks reminded me of a question I'd love to ask you about rekenreks. I have a class set and need to know how to better use them. I'm currently in the midst of a number sense & place value unit. Does it make sense to introduce the rekenreks now?
    ❀ Tammy
    Forever in First

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    1. Hi Tammy,
      It absolutely makes sense to introduce the rekenreks now. They are a great tool for kids to use to build number sense, subitizing and addition and subtraction facts. Here is a link http://www.mathlearningcenter.org/snr to a free app and a free booklet about using the rekenrek in your classroom.

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  2. How did you make the bead sticks?

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    1. They are made out of bamboo BBQ skewers. The end caps are sold as doll heads at a craft store. I have not been able to find the doll heads in that size for the last few years. Some folks use a wooden bead with glue in the end but I have always had more luck with the doll heads when I can find them!

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  3. What materials did you use to make your 10 bead sticks?

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  4. Should you make them with two different colors or would all one color be okay?

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    1. Great question! I think two different colors is super important! The two colors eliminate the need to count the beads. They know they can make 7 by sliding 5 and 2 and so on. I don't think they would be nearly as effective if they were just one color.

      The materials can be hard to find, especially the doll heads. If you can't find all the materials, the Math Learning Center puts out a kit to make something similar. Check it out: http://catalog.mathlearningcenter.org/store/product-8557.htm

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  5. Hi! I love your idea on the counting sticks. I went out an actually found doll heads in the craft section at Wal-mart. However, the pony beads I purchased do not fit on the BBQ skewers. Did you use regular pony beads?
    Thanks!

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    1. I see wooden doll heads at WalMart. There are two sizes. Do I want the 1" or the 1 1/2 " doll heads for the counting sticks? Thanks.

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  6. Stephanie, there are two sizes of pony beads at least. You might have purchased the smaller ones.

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  7. Lesson learned! I never knew there were two sizes of pony beads! I am so excited to make these for my RTI Math kiddos! Continued Success! :) Thanks Math Maniac- Amazing Idea!!!

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    1. Thanks Stephanie! I had not idea there were two sizes of pony beads either or I would have warned you! I guess if you see two sizes, get the bigger ones! Thanks for sharing that you found doll heads at WalMart! I will have to look! I haven't been able to make more of these for the last 3 years. My supply is getting low because I often let kids take them home!

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  8. Replies
    1. In the summertime I can usually find them at grocery stores and drug stores. If it is not BBQ season, I order them on Amazon.

      Here are the ones I get on amazon

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