Teaching 2-3 digit subtraction strategies is one of the most difficult skills to teach! Seriously, it can be SO tricky, but today I want to share with you 4 2-3 digit subtraction strategies that will help your students develop a deeper understanding of subtraction.
These strategies do not focus on the standard algorithm.
If you’re looking for 2-3 addition strategies, you can read all about them over on this post!
In this post, you’ll see pictures using my subtraction strategies resource, but you can implement these strategies with just paper and pencil!
Before you teach 2-3 digit subtraction strategies
Just like with addition strategies, it’s important to help students discover these strategies. One of the best ways to do this is through number talks. As the teacher, I strategically choose the numbers in the subtraction problems I give them to solve.
2-3 Digit Subtraction Strategy #1: Hundreds Chart
As you’re beginning 2-3 digit subtraction, I like to start with a problem where students are only subtracting multiples of tens. For example, I might write 65 – 20 = __ on the board. Most students will quickly know it’s 45.
While I write down the different ways students might get that, I pull out a big hundreds chart and ask if they can show me on it. Students quickly realize that they can “hop up” to subtract tens.
Then I ask students, what if the problem was 65 – 23? How can we still use our hundreds chart? Students will see that they just take 3 more away. The hundreds chart is a great visual! Give students their own little charts to practice!
Subtraction Strategy #2: Base Ten Blocks
I really like to show students the base ten blocks after using a hundreds chart. Because students should already have an understanding of place value, we can draw the blocks or use actual blocks to practice.
As a note, I would start by showing students problems that do not require borrowing. Remember, you need to strategically choose the subtraction problems you pose. Once students are comfortable, then you can pose more challenging problems that will require students to borrow and break apart some tens.
Subtraction Strategy #3: Break Apart
Just like with addition strategies, there are multiple ways for students to show what they’re thinking. Make sure as you give students problems to solve that you listen very carefully to how they solve them.
For example, if we go back to our original problem: 65 – 23, a student might first solve 65 – 20 = 45 and then 45 – 3 = 42. Another student might subtract the tens (60 – 20 = 40) and the ones (5 – 3 = 2). Then, they put them back together to get 42.
As you can see, there are multiple ways students might break apart (decompose) the numbers!
Subtraction Strategy #4: Number Line
Sometimes the number line strategy can be the trickiest of them all. I know most teachers have students count back hundreds, tens, and ones on the number line. This strategy is especially helpful if students struggle with borrowing.
However, have you ever thought about teaching students to count up on the number line? For example, let’s say you had the problem 20 – 17. Many people would quickly realize that the answer is 3 by simply counting up.
What if we tried that same strategy with bigger numbers? While some of your students might not fully grasp it YET, you may have a few students who love this strategy simply because counting back is hard!
Subtraction Strategy Squad
Throughout this post, I’ve shown you some of my favorite strategies. As students learn these strategies, I introduce the Subtraction Strategy Squad. These strategy friends help students remember there are multiple ways to solve subtraction problems!
I have tons of strategy posters, centers and printable practice pages you can use in your lessons for students to practice these various subtraction strategies!
Read all about the addition strategies over on this post!