My Addition and Subtraction Epiphany

So we just finished up our math unit on addition. In previous years we really only taught addition, meaning "this+this=this", not really getting too much into reversing the equal sign and surely not doing anything with missing addends. Enter Common Core...(everyone has their opinions, I know) Our new math series has an entire section on finding the missing addend in sums to 10. I admit I was hesitant to teach the concept because it is so abstract. However, I dove into it head first. I put a box of math manipulatives that came with our series on each table with enough for each student to have a set. For the past 2 weeks I've been putting out the worksheets that came with our series where students had to find the missing addend. It was tough at first, lots of modeling and breaking it down and frustration. However, the more we did it the easier it got. I began explaining to them that they "start with the total" and then "take away the number they show" and then "count how many you have left". What? Wait, you mean...I'm setting them up for subtraction? YES! This was my AHA moment this morning. In teaching them to find the missing addend I've been setting them up with CONCRETE FOUNDATIONS that will help them more easily understand subtraction. Wow, how silly of me to have not realized that before. It just goes to show how intertwined the concepts are in math. For those of you who already do this, HOORAY! You're awesome. For those of you who haven't taught the concept yet, I highly encourage you to do so. I can't wait to see how much easier subtraction is going to be for my kiddos!!