Addition with Regrouping Using Base Ten Blocks: 2-Digit Numbers
Addition with regrouping using base ten blocks is part of the 2.NBT.5 standard. Students need to be able to add 2-digit numbers with and without regrouping.
Addition with regrouping can be challenging for students if they don’t have strategies to use. It is also the next logical step after teaching addition without regrouping. Once students are familiar with numbers that do not require regrouping using base ten blocks, break apart, and an open number line, you can move on to teaching all three strategies with numbers that require regrouping.
Just like starting with base ten blocks without regrouping, that’s the strategy I like to teach first when teaching regrouping. It just helps the students visualize the numbers better. You should use the physical base ten blocks to start and then move into drawings of base ten blocks. Finally, you can teach students how to draw sticks and dots to represent the tens and ones.
I love using these magnetic base ten blocks when teaching this strategy. You can model on the board or have students show the class how they solved problems with these.
Keep reading to learn more about this strategy and to find a resource you can use right in your classroom to teach 2-digit addition with regrouping using base ten blocks.
Addition with Regrouping Using Base Ten Blocks Example
What do you think you would do to start solving 29 + 14?
If you said, build 29 and 14 using tens and ones, you are correct! Great job!
Once you have the numbers built with base ten blocks, you will need to regroup the ones into a ten.
Start by moving a one from the 14 over to the 29.
Now you have ten ones. Regroup those ten ones into one ten.
To show that, you will take the ten ones away and put one ten in their place.
You now have 4 tens and 3 ones. The sum is 43.
Addition with Regrouping Using Base Ten Blocks: Drawings
Once the students master solving 2-digit addition problems using the physical base ten blocks, you can move to base ten blocks on paper. Let’s use the same problem again.
When the students are solving problems that do involve regrouping, they need to show how they regrouped the numbers in order to add.
The first step is to make a group of ten ones. When using the physical base ten blocks, students can move one from 14 and put it with the 29.
It isn’t possible to move drawings of base ten blocks, so you have to draw to show the regrouping.
When drawing base ten blocks, you should show the group of ten by circling ten ones.
After you circle the group of ten ones, you want to show how you regrouped that into another ten. So you draw an X over the circled group of ten ones and replace it with a ten.
Then you are ready to count the tens and ones.
Important Note: Make sure you DO NOT count the ones that are circled and you DO count the ten that you used to replace the ones.
You now have 2 tens from 29, 1 ten from 14, and the additional ten from regrouping the ones. That makes 4 tens.
You are left with 3 ones after you regroup ten of them.
The sum is 43.
Once the students master using base ten blocks to show the regrouping, you can take it a step further.
Addition with Regrouping Using Base Ten Blocks: Sticks and Dots
You can introduce sticks and dots as a simple way to draw tens and ones. If you taught this way when adding numbers without regrouping, your students should be familiar with it.
When using sticks and dots, you can just give the students the problem and they can draw sticks and dots to solve. This saves you time and gives your students the opportunity to show their thinking.
Students will show their regrouping in the same way they did when using the drawings of base ten blocks.
The first step is to regroup ten ones into a ten. Circle ten ones.
Cross out the ten ones and draw one ten. Now you are ready to count the tens and ones.
There are 2 tens from 29, 1 ten from 14, 1 additional ten from the regrouping, and 3 ones leftover.
That adds up to 43.
Addition with Regrouping Using Base Ten Blocks by a First Grader
Addition with Regrouping Using Base Ten Blocks: 2-Digit Practice
Do you need some practice pages for your students to use with this strategy?
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