Last week, I introduced my Grade 2 students to addition with regrouping. Usually this is one of the hardest math units that I teach all year, but many of my students already knew how to regroup, and they picked up on this quickly. They were explaining their thinking well, and even helping each other out along the way. I know that we still need to work on developing this skill, especially with more problem solving opportunities, but when my wonderful Grade 1 teaching partner said that she’d take my Grade 1 students last period today so that I could just work with my Grade 2 students, I knew that I needed to introduce my next challenging unit for the term: subtraction with regrouping. Let’s just say, it was a lot more complicated than addition. I guess I knew that it would be. I taught these units last year to my Grade 2 students, and they struggled more with subtraction as well.
After school though, I sent out this tweet:
I got many replies to this tweet, including this one from Carol McLaughlin @missmac100, a Grade 2 teacher in Alabama:
Carol gave me perspective. Maybe this is a concept that just takes time and patience to develop. When I came home today and started watching these videos from our exploration activities, I started to have more hope:
No, the students didn’t get the right answer the first time. And yes, they sometimes forgot one of the steps, but they were doing better as time went on. They could be talked through what to do, and they were communicating their understanding of the concept, even if their answer wasn’t always correct. We’re not done trying, but maybe I just need to give the students some more time, and some more practice, to really get subtraction with regrouping. What do you think? What teaching strategies have you used to teach this difficult math concept to your students? Thanks for your help!
Aviva
Yes, it takes lots of time and they need different experiences with subtracting. We started out with manipulatives playing a game called “Race to Zero” on teacher created “place value” boards. It helps them understand that you can trade to subtract when you need to. I also have lots of “replay note” teaching videos on my twitter page @missmac100 that show the various ways we explored to solve problems with regrouping. I love that every child has a way that makes sense to them. We just learned the traditional algorithm but we did not do that until we learned ways that keep the place value intact and with meaning. 🙂
Carol, I love the videos that you created, and your “race game” example just gave me an idea. It reminds me of a stamp game in the Fosnot kit that I think I can modify to work. Thanks for giving me even more to think about, and thanks for the comment too!
Aviva
It looks like the students were really making connections with the base ten blocks. I agree with Carol about using place value mats because it will really show the concept well. I also like using open number lines as a tool for subtaction to help with the development of mental math strategies later and show how we can use decomposition of numbers to solve problems.
Thanks Kelly! I’ll definitely be using both of your suggestions (yours and Carol’s) as we move on with this difficult concept.
Aviva