Sunday, April 8, 2012

Subtracting to Decompose Numbers - Still Interacting with the Common Core!

Wow! I am thrilled to received such a positive response from my Decomposing Numbers Addition Activity Sheets. A number of people requested subtraction pages as well. You want it, you got it! Decomposition by Subtraction!

Did you miss the addition post? You should check it out!
Getting Interactive with the Common Core: Decomposing Numbers

These are set in a similar format to the addition activity sheets. Subtraction can be a bit trickier to represent on paper, so the pages have been adjusted to fit the concept in a way that is (hopefully) minimally confusing for little learners. Instead of using 2 colors of 1" tiles, students only need to use tiles of 1 color. They will need to glue a tile onto every square on the page, then write an "X" to represent which tiles are being subtracted. Just like the addition pages, students will then need to translate the tile representation into a subtraction number sentence.

Decompose 9 by Subtracting
Subtract to decompose numbers in kindergarten

I went around and around about the best way to set these pages up:
Should I stick with the 2-color tile combination?
Would that be too confusing to students?
Should I have students physically remove the tiles after they are glued to LITERALLY take them away?

Should students use just 1 color and X the ones that are subtracted? 

It was quite a mental debate. Ultimately, I decided to use one color and have students write an X on the items they were subtracting. If there is a demand for subtraction worksheets with different instructions, I can create a new set to fit that need.

I have 2 sets of activities available for download. Set 1 has Subtraction Decomposition worksheets for numbers 4, 7, 8, and 9.  These pages are all formatted to print on standard letter-size paper (8.5"x11").  The activity pages for 7, 8, and 9 are two pages each. They are intended to be taped together and copied onto sheets of 11"x17" copy paper. My kiddos always love working on a really big piece of paper.

Subtract to decompose numbers in kindergarten

Set 2 has Subtraction Decomposition worksheets for numbers 2, 3, 5, and 6. These files are formatted to be printed on legal-size paper. For the document to print properly, you may need to adjust your printer settings.
To do this, open the PDF, then go to File->Print Setup. There should be a drop-down box that allows you to select "Legal."

Decomposing Numbers Activity Sets, $1.50
Shop Decomposing Numbers on Teachers Pay Teachers
Shop Decomposing Numbers on Teachers Notebook


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