I am a huge advocate for teaching students the WHY before the PROCEDURE when learning a new math concept. I am a firm believer that teachers owe it to their students to teach them multiple ways to solve math problems. We all learn concepts in different ways and math is no different.
Before I start my addition with regrouping unit, I spend a month teaching place value. Students must be solid in their place value understanding to truly understand the WHAT and WHY of addition with regrouping. The first day of teaching this skill, my students receive unifix cubes and they learn what regrouping looks like. You can also use place value blocks but I like that unifix cubes can be pulled apart and pushed together. We always start with a two-digit number on top and a one-digit number on the bottom. Here’s how I teach it:
As I am going through this lesson, I have students who seem to be able to grasp the concept, come up and show the class how to do it all while explaining what they are doing. When students explain their thinking and thought process, it is extremely powerful.
After a day or two of teaching this concept using the place value mat, I will have them move to paper and pencil solving but still provide them with their unifix cubes and place value mat to build and solve each problem. Make sure to scoop up your FREE place value mat before going any further!
One tip is to give your students highlighters and have them go through their worksheet and highlight the ones place so that they have the visual reminder of where to start solving their math problems.
Be watchful of those who just want to take the two-digit number and count on. Although this is a practical way to solve these problems, you must be also thinking about the concept that you are trying to teach them…regrouping.
Next, we move to two-digit numbers on top and bottom. Of course, we go back to the math manipulatives to help them see and understand the process of regrouping.
We continue to highlight the ones place at this stage. I want to make it a habit for my students to always start with the ones place first. This concept is more complicated for them then we realize. They are trained to read and write from left to right so starting them on the right side of the problem tends to cause some students to struggle.
As I stated at the top of this post, I am a firm believer in teaching students multiple ways to solve problems because you never know what will connect with them. Here are a few more ways that I have shown my students how to solve addition with regrouping problems.
Post-it Note Method
Break It Up Method
Slice & Split Method
Are you looking for some addition with regrouping resources? Here you will see an Addition with Regrouping Interactive Math Notebook Unit and QR Code Task Cards. I use both of these resources to teach my addition with regrouping unit.