Taking Numbers Apart

This week in kindergarten, we've begun to look at numbers in a new way. We've started to compose and decompose numbers. These are strange terms, but it's pretty easy - it looks like this:

4 is 0 and 4.

4 is 1 and 3. 4 is 2 and 2. 4 is 3 and 1. 4 is 4 and 0.  This concept can feel pretty frustrating for some students at first. So, today before delving into composing and decomposing numbers, I equated decomposing numbers to learning how to ride a bike without training wheels. It feels like you'll never learn how to do it, but all of a sudden, you're peddling down the street with only two wheels! They really enjoyed hearing that! (CC.K.OA.A.3 - Understand addition as putting together and adding to, and understand subtraction as taking from.) Here are a few of the Math In Focus workbook pages we completed today.

Here is how we start out. Tell how many cubes of each we have and then how many do we have all together?

Then we choose our own combinations to 4 and 5. The students have to tell me how many of each they chose to color, how many of each they have, and then 5 is ____ and _____. This is the part that feels like that bike without training wheels!

This student decided they were going to put 3 blue and 2 yellow cubes together to make 5.

This student's first combination to 5 was 4 and 1.