I am new to 2nd grade and just wanted a clear understanding on addition strategies. For the past few days we've been working on Doubles and Double plus one. Most of my students are dong well with adding, especially with doubles but they are not getting the doubles plus one. How important is the doubles plus one and doubles minus one strategy? They don't understand the strategy but they are adding. I don't want to stress over something that is trivial in the scheme of things. I still working on my math block and once I move on I know that we still be working on previous taught concepts but I don't want to spend more time then needed.
Doubles and doubles +1, -1 are VERY important. Once students have their doubles mastered, it is crucial for them to be able to use those doubles to get the answers to other facts. If a student knows 6+6 then she can get to 6+7 (doubles +1) or 6+5 (doubles -1).
Yes, absolutely teach them. They are one of the math fact strategies that your students need.
They are really struggling with this. They know doubles and they can add 3+4, 5+4, and even 10+10 but I see them using their fingers so much. They're quick with the doubles but not the idea of plus 1 or minus 1. Once I asked them what's 10 + 11, I lose them. I don't like all the ways that the curriculum is telling me to teach it. I'm going to have to look for another way for them to get it. Last year, I spent so much time on smaller concepts I just had to asked. I don't want to get behind. Maybe I can find some good workstation games.
Could they just be a little young to really understand how they would use that strategy? I might back off and revisit it later in the year.
But you could always try the ultimate manipulative - themselves:
Ask for three volunteers. Bring them up to the front of the room. Then ask for three more, and bring them up. Ask them what addition sentence they just made, and write 3+3=6 on the board.
Now bring up one more kid, put him with the second group, and ask for the new sentence. Write 3+4=7 exactly underneath the first problem, and let those kids sit back down.
Keep repeating problems like this until everyone has had a chance to volunteer, and you have a few pairs written across the board.
Now ask "What do you notice about the pairs of number sentences you made?"
Be interested in everything they give you, but you're especially looking for them to say that each time one of the pieces has gotten bigger by 1, so has the answer, or that they can get to the second sentence from the first one, things like that.
Then if they get it with +1, you can do -1 the next time.
The first thing I always do is just spend time having kids decipher which strategy to use. This was always the hardest part for my students. They would see a fact and not know when it was appropriate to use which strategy. With doubles +1, we talked about the numbers having to be next to each other on the number line. I would give facts and they would give a thumbs up/thumbs down if it would work for the strategy. Then as I introduce other strategies they would be given facts to sort into different strategies (of course some can be done using more than one strategy). I found once they had a firm understanding of WHEN to use this strategy, it was easier for them.
I have a cd that has addition strategies (something to do with Addition baseball or something like that) and it has a song for doubles +1. One of the lines in the song says "You double the smaller number and then add one, how fun!" I found myself repeating this line all the time when doing think alouds and even heard students saying it to themselves as they did their independent work. They really like that song (although I find it a bit annoying).
I have a Doubles and Double plus One song on an Addition CD from Twin Sisters. The kids LOVE it!!! Also, consider reading Two of Everything to your students and having them make a "magic pot book" (one for the whole class).
This is a really important skill and I spend at least 2 days reinforcing it.
Hi 2ndGradeMama. I have the students help create their own doubles song with my help. We print this and add to homework. They are going to one of the lower grades 1=2 to present this skit next week. Sometimes they take them home and try to find another rhyme, or think up better actions. The song we made this year is at school but I will try to type it and sent on Monday if you are interested. We sing the song then, later start using the ants go marching around the classroom. Then follow this anoher day with adding one more. Students love it!!! The Ants Go Marching is on this site if you search past posts. Hope this helps. Remember they will not all get this, with continued practice throughout the year they do finally (for the most part) understand. Hope this helps I am completely computer dysfunctional so I have no idea how to attach the song but is great to add to brain action activity when they start to shut down. We actually use this game as a reward activity for a successful day. Students are working hard on Respect issues so they can present song to grade 2 this week. Hope this helps.
Does anyone have posters of this strategy. My students have always been strong with this skill...but this year they have looked at me like I was crazy...SO we will be working on this and learning the doubles using numbers. Thanks for all the ideas.
The CD is the one the pp mentioned. It is called "Addition" and is put out by Twin Sisters. The cover has a picture of a cd playing baseball. I bought it off amazon. I have to admit, it is a pretty cheesy cd, but it gets stuck in your head so I guess it serves its purpose.
I use their phonics CD. I used it last year with my kindergarten class so it was okay to be a little chessy. This year what I going to is write the lyrics on chart paper like a poem and read it first. Then I'll bring the song it. I like twin sisters because most of the songs and CD's I find are so expensive. I definitely will look for the addition on. I Google them earlier and the prices are real reasonable.
I have taught 2nd grade in a Title I school for a very long time. I think the doubles +1 strategy is very important.
However, as someone pointed out not everyone is ready for the same strategy at the same time. Some of my kids get it right off and some of them can use it with assistance and some of them just don't get it. I try to point the strategy out all year long in hopes that more students will be able to understand and use the strategy. But I have also accepted that some just won't get it.
That, of course, doesn't mean that they won't get it later. We also teach doubles +2 and doubles +3. Some of the kids connect with the strategy and some of them don't. These are "strategies" and not everyone will always use the same one.