Addition and Subtraction Strategies

We spent 2 full weeks working on adding and subtracting double digit numbers with borrowing and regrouping. This is definitely a tough one. Having never taught this in first grade, this was definitely a learning experience for me and for them.  But, on a happy note, my kids aren't freaked out by it.  I used my CGI (Cognitively Guided Instruction) training from my previous district, we worked on strategies to make it concrete and they're getting it! 

The three strategies we're focusing on are....

Place Value - using sticks as the tens and dots as the ones - great strategy for kids who struggle.  Helps them to see it out like the base 10 blocks - great way to take it from manipulatives to no manipulatives.  Below, the student took the nine ones from the top and the one one from the bottom to make a ten - see the arrow.



 

Empty Number Line - starting with the larger number on a empty number line and counting up by 10's, then 1's

 

 

 Break Apart Strategy - this one is my favorite - see 2 different ways below of breaking the numbers apart...

 

 

Here are our anchor charts that we made for Adding and Subtracting Double Digit Numbers with borrowing and regrouping - each strategy is listed with an example.  I let students practice all of the strategies then they can pick the one that works best for them.