Since we use thinking maps a lot at our school, I decided to base my instruction about decomposing numbers on a brace map model. In addition to this, the students use place value mats and base-ten blocks for a more hands-on approach with this skill.
First, we build the number with base ten blocks.
Then, we break the number down into tens and ones. The students document this on their "Decomposing Numbers" page as well. (This part is nothing new; we have been using base ten blocks and reviewing place value all year long.)
The students remove the tens as their first step in decomposing. Using the remaining amount of ones, we break this number down into a familiar addition fact. Again, the students document this on their "Decomposing Numbers" page.
At this point, we stop and focus on the way our brace map helps to break the numbers down. The students focus on the outermost numbers on their braces, and use those numbers to build the final addition sentence.
Again, this is just the beginning of my instruction with decomposing numbers. I thought it would be a good place to start since this process is the most logical in my mind. However, logic within my brain does not always mean it is the best way, so if you have any ideas, PLEASE feel free to share those with me! I would love to see any approaches other teachers have used to teach this skill.
If you think you could use method, I will gladly share my "Decomposing Numbers" page with you! Please feel free to e-mail me with a request for the file, and I will email it back to you as soon as possible. However, I will recommend that you use a MacBook for downloading/editing. The font type I used to create the page may not be compatible with Microsoft programs.
Hope this is helpful! :)
UPDATE: THIS BLOG POST WAS CREATED BEFORE I ESTABLISHED A TEACHERS PAY TEACHERS STORE, WHERE I NOW HAVE THIS PRODUCT AVAILABLE. TO ACCESS A FREE VERSION OF THIS PRODUCT, SIMPLY VISIT THE TALLY TALES TPT STORE HERE. THANKS SO MUCH!