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How to Teach Subtraction with Regrouping in 5 Simple Steps

 Teaching subtraction with regrouping using the standard algorithm? You’re in the right spot! But, if you are teaching 1st or 2nd grade, please remember, the written algorithm for addition and subtraction isn’t necessarily the end goal! 


Your students need to use strategies based on place value and relate them to the written strategy. Can the standard algorithm be the written strategy you are relating their place value thinking to? Sure thing! But if your first or second grade students continue to need hands-on materials or representative drawings – don’t stress! They are exactly where they need to be. 

Those caviats aside, let’s talk about how we can move students from hands-on to a written method! 


1. Start With A Groupable Model


Start with a groupable model such as linking cubes. Bundles of straws also work fantastically! You want to use a tool that will allow your students to literally unbundle a group of ten into ten ones if needed. 


Using these tools on top of a place value chart helps to keep work neat, organized and lends itself to a written model down the line. 


2. Move To A Pre Grouped Model



When your students are consistently successful using a groupable model, move to a pre-grouped model. The place value disks shown above are one option but base ten blocks, a proportional pre-grouped model are also a valid option! 
This will be more difficult than the groupable model because your students need to know that a ten is the same as ten ones- they can’t rely on the manipulative. 

3. Link To A Written Method



If your end goal is a written algorithm you want your students to link the hands-on tools they are using to the written method. Demonstrate and expect that manipulatives and written methods are used alongside one another. 
Asking questions such as “I see 5 tens on your place value chart. Where did you show those 5 tens in your writing?” can help your students to make connections. 

4. Move To A Representative Drawing


When your students are consistently successful modeling subtraction using hands-on tools, consider moving to a representative model such as drawings on a place value chart. This is an intermediate step that will support your students in moving from concrete (hands-on) to abstract (the written method). 

Just as you introduced the written method alongside a hands-on model your students were already familiar with, you can (and should!) do the same when introducing representative models. 

For example  “We had 8 ones and took 6 ones away using place value disks. What would it look like if we took 6 away from a place value drawing? Let’s show that on our white boards!” 


5. Link To A Written Method (Again) 


At this point, your students are confident using multiple hands-on tools to represent subtraction, they are also regularly successful using a place value drawing or a representation on a place value chart. Your students are able to use a written method alongside their hands-on tools. 
The final piece of the puzzle is to ask your students to relate their representative drawing to the written method. Just as you did in previous steps, explicitly discuss with your students the steps they are taking when solving problems using a representative drawing and show how they can model this exact same action using numbers. 

That’s it! Now, follow these steps yourself or grab my ready-made unit. You will find pre and post assessment, five lessons (hint- they follow these five steps!), independent practice to mirror each lesson and exit tickets so you can progress monitor along the way! 




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