Common Core Chat: Subtraction Strategies for Seconds

Greetings all! 🙂 Today I’ll be sharing with you one strategy I’m using with a few of my advanced math students to understand how to regroup while subtracting. Differentiation is always encouraged in the classroom. While the majority of my students are at this time of the year embracing the first grade standards in math, I have a handful that I have been pulling aside to work on the companion standards in second grade. It’s been a ton of fun to have my kids do these videos when they’ve learned to share their thinking! 🙂
In this video, one of my girls is solving her subtraction problem using expanded form. Expanded form for firsties may seem imposing, but, its one way to get kids to really understand what they are taking from the adacent column. This is foundational to performing more complex tasks with number sense.

This student is working on mastering the following mathematics strategies:

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.

CCSS.Math.Content.2.NBT.B.9 Explain why addition and subtraction strategies work, using place value and the properties of operations.