Hello again, everyone! 🙂
Last time we had a Common Core Chat, I shared with you a little bit about how I was teaching addition strategies to my firsties. This week, I’d like to share with you how I’m teaching subtraction strategies. One of the goals of common core instruction is to teach more deeply. The important thing to remember is that it is not enough for your students to know the steps of addition or subtraction, but the WHY behind it. When they are able to talk to you about WHY numbers are configured the way they are…the sky is the limit for what they are able to gain…especially in first grade!
I have worked on building a foundation for this ALL YEAR. It’s not something that the kids just learned over night. Tens and ones instruction is part of our calendar time, and using strategies to add and subtract as well. The goal of first grade math instruction as it relates to basic facts is that students would have automaticity of facts with sums and differences to ten. They can add and subtract up to 100 with strategies.
In the videos below, you will see a few of my students working through some subtraction problems. The standard that these students are working on is…
2.NBT.B5 Fluently add and subtract within 100 using strategies based on place value, properties of operations, and/or the relationship between addition and subtraction.
Based on our small group work, I’ve determined that these students are ready to tackle the second grade standard for addition and subtraction. Check out our videos to see how they are working towards subtracting two digit numbers without regrouping.
In this first video, my student is breaking down tens and ones to solve a two digit by two digit subtraction problem without regrouping. He first subtracts the tens, then the ones, and finally adds the differences together to get a composite number.
The next video is a video of small group work time with students who are also working on this standard. In my classroom, I have seven students working on the mastery of this standard. In this group, the first student uses the same strategy that he used in the first video. The other two students used an expanded form strategy to solve the problem. Its really neat to see them starting to dive into math! I’m going to miss this group of firsties so much!
Thanks so much for stopping by today! 🙂