This is such a tough topic for second graders!! Anyone have any tips when students are first learning how to do this??

We used base ten blocks and paper today for our second lesson in the unit (pearson envision topic 8) and I had a lot of "I don't understand this" comments.

We watched a brain pop video and I modeled a LOT...but there were still a few who didn't follow.

Repetition in many different ways has always helped my students. I'll present 2-3 problems the whole class period and I break students into groups to attempt the problem with any manipulatives and paper then need (I usually give them a half- or quarter-sheet of chart paper and they're in seventh heaven).

When we come back together, students practice showing how they did a problem and explaining why they did what they did. Once we gather many ways, we discuss any misconceptions. If there are strategies that weren't used, I model those as a whole group.

Usually they understand one of the strategies and I use that to help them understand the others, specifically the traditional algorithm. It can be the quickest, but until they understand the reasoning behind it, it's really hard for them to do it.

Below is an anchor chart I created with my class last year.

For most of my students it took a lot of repetition.

We use Math Expressions, which introduces them to a few different strategies. I used base-10 blocks, and then switched to drawing a picture. Most students were successful with both strategies. I then moved onto the traditional algorithm. This is when it all clicked for most students. It took them about 4 weeks to get it. :/

Isn't Envision fun?. I used the base ten blocks for two days before even giving them the work sheets.

It's the subtraction that is brutal for a few. To piggy back on PP's poem, for subtraction we say "If there's more on the floor, go next door." Again, lots of manipulative use. I was surprised that after two weeks of this, two kids were still mystified. Discovered one of them has very weak number sense. The other just need LOTS of practice.

The traditional algorithm isn't supposed to be taught until fourth grade. Instead, 2nd graders should be adding/subtracting using strategies based on place value, properties of operation, and the relationship between addition and subtraction. One of the previous posters had several of those strategies on an anchor chart.

My district is in the first year of Common Core for 2nd grade, and they are correct, CCSS has the standard algorithm being taught in 4th grade (even our state had it as a 3rd grade standard prior to adopting Common Core). I don't teach that method, and I try to discourage parents from teaching it, because it can throw the students off. I instead really focus on place value and number sense.

The anchor chart someone else had posted was a really good example of ways to use number sense to add 2 (and 3) digit numbers using things beyond the standard algorithm. At this point in the year, I'm just teaching/modeling drawing base tens blocks, breaking numbers into tens and ones, using 100s charts, and breaking numbers into other groups/landmark numbers that they do know. I only have a few students that are starting to make that jump (almost every single student still wants to draw 25 circles and 39 more circles when adding 25+39, but we use that as a starting point and jump from there), but a few is more than I had at the beginning of the year, and I know that it typically takes my class almost the whole year to use other strategies, to the point that the only students I typically see using circles/tallies or counting by 1's the whole way are my lowest students.

It's just a thought. If you aren't using Common Core, then this post doesn't really apply to you, but if you are then I wouldn't really be stressing the standard algorithm.

When I taught this skill to my mostly kindergarten level second graders this year, I used post it notes to model the "carry the tens". I would add the ones and hold up post- it notes with the answer. (Ex. 4+9=13). I would put the post its with 1 and 3 under the 4 and 9 and show that there isn't room for both in the ones places. Then I would move the 1 into the tens column and add it. It made a huge difference!
I hope this makes sense!

It is an interactive site that models what is happening in addition and subtraction when regrouping.

I haven't had any trouble teaching addition regrouping as long as I did adequate place value preparation beforehand.

Subtraction regrouping is harder but most kids got it after watching me manipulate the base ten rods on the above site. I also use the poem

Is there more on the floor? Then go next door and borrow ten more.
Is there more on the top? Then stop, subtract.
Are the numbers the same? Then zero's the game.

Keltikmom,
What is it you don't like about Envision? Some of our teachers want to pilot it. I am interested in hearing some of the negative things about it.

Do you feel it goes well with the common core?
Is there enough for your students to master all of the standards in the core?
Do you have to supplement?
Are your students being successful?

I agree with the others, it takes them a week or two to get the hang of it. We are teaching the "break apart" method, but we began by using and then drawing base 10 blocks. I start with 2-digit plus 1-digit, such as 47 +6. Then I have them draw 47 (tens and ones), add the 6 ones, and circle 10 ones to count as a ten. My middle and advanced students have now pretty much got the hang of breaking the numbers apart without drawing, and my lowest few are still at the drawing stage.