When the Common Core rolled out, I know lots of people were slightly distressed about teaching students multiple ways to solves problems. Or maybe not people. Maybe just parents that were totally unfamiliar with the strategies.
"What do you mean there is no crossing out and carrying! We only carry in this house!"
Or something like. Or maybe something like this?
Or like this?
Yeah. At my school, too.
I worked really hard to teach the parents as much as the kids because it is a huge shift in thinking.
First, I always get the question, "Do you really teach your kids ALL the strategies?" Yes and no. I don't teach all the strategies because there are so many, but there are several that I do teach.
The CCS in second grade states:
CCSS.MATH.CONTENT.2.NBT.B.5- Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
CCSS.MATH.CONTENT.2.NBT.B.7- Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in adding or subtracting three-digit numbers, one adds or subtracts hundreds and hundreds, tens and tens, ones and ones; and sometimes it is necessary to compose or decompose tens or hundreds.
So it doesn't explicitly WHICH strategies to teach- just that it need it follows "place value, properties of operations, and/or the relationship between addition and subtraction."
So many strategies fall under place value (in my opinion).
I stick to four main strategies: adding with base ten blocks, adding on a hundreds chart, adding with place value, and adding on an open number line.
These are my personal preference and you may be mandated to teach other ways (especially with mental math and Number Talks) by your district.
When teaching about the strategies I like to create a chart like this to show the different strategies for solving the same problem. I don't fill in the chart at one time, instead we fill it in as we learn each strategy.
This chart stays up for a long time and is a great reference and reminder for kids!
As far as what order I teach the strategies, I always start with base ten blocks. They are the most concrete (and familiar) of the strategies. I don't actually have much to share on that strategy since it is nothing fancy! LOL!
When the numbers are within one hundred, I usually move on to teaching adding on a hundreds chart. I like to use three color tokens when teaching this.
We had these available at my school. If your school does not have them, you can buy them super cheap on Oriental Trading.
The first color token is the starting number. Then, I use two separate color tokens to show adding with the tens and ones. I think it just makes it easier for students to visually see how the "hops" work. Eventually, kids move to using a dry erase marker on the hundreds chart to using just their fingers to make the hops.
If you are looking for more practice to teach this strategy, I have this pack in my store. It has over 30 pages of practice for only $3.00!! Click here to check it out!
I like to teach this strategy before jumping into adding with place value because it reinforces adding the tens and the ones.
This is my MOST favorite strategy Simply because it is how I choose to add mentally! It takes a good bit of modeling and I always go BACK to the base ten blocks to model it first. Then I relate the blocks to a written method like this:
Do you like this work mat? Laminate it so kids can build with the blocks OR draw on it with a dry erase marker!
Adding with place value can be a tough strategy to find resources for so I have a 15 page FREEBIE of all kinds of goodies for you- including a whole class game of scoot!
Truth time: my least favorite strategy for addition (or subtraction) is an open number line. My brain just does not work in a linear line! LOL! However, I DO teach it to my kids, in case they get it. This tends to be a more difficult strategy to explain to parents.
I like to send this parent letter home for a reference. This is another strategy where there just aren't too many things out there. I made this pack in my store.
There are over 20 pages of practice for only $3.00! Click here to check it out!
Do you teach any other strategies? What are your favorites?