3 Digit Addition without Regrouping Using Base Ten Blocks
Addition without regrouping is an important pillar to teaching students how to add 3-digit numbers. It was my starting point for teaching 3-digit addition. I spent many days teaching 2.NBT.7 to build on the 2-digit foundation for students. No need to rush through these lessons. Students need to master addition without regrouping before they can understand how to regroup the numbers.
There are many strategies for adding 3-digit numbers, but I like to start with using base ten blocks to represent the numbers. It helps students visualize the numbers. 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 3-digit addition without regrouping.
3 Digit Addition without Regrouping Example
What do you think you would do to start solving 135 + 123?
If you said, build 135 and 123 using hundreds, tens and ones, you are correct! Great job!
Once you have the numbers built with base ten blocks, you will combine the hundred, tens and ones.
At this point, you will count the hundreds, tens and ones. Since you do not have to regroup the hundreds, tens and ones, the answer is simple. There are 2 hundreds, 5 tens and 8 ones, so the answer is 258.
3 Digit Addition without Regrouping Using Drawings of Base Ten Blocks
Once the students master solving 3-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 not involve regrouping, they can count the hundreds, tens and ones and write the answer. There is no work or thinking to show on paper.
However, this is what it looks like if you combine the hundreds, tens and ones and then count.
Once the students master counting the hundreds, tens and ones to get the answer, you can take it a step further.
3 Digit Addition without Regrouping Using Squares, Sticks and Dots
You can introduce squares, sticks and dots as a simple way to draw hundreds, tens and ones. When using squares, sticks and dots, you can just give the students the problem and they can draw squares, sticks and dots to solve. This saves you time and gives your students the opportunity to show their thinking.
Again, you don’t have to show any work to find the answer with squares, sticks and dots. The image below shows what it looks like when you combine the hundreds, tens and ones to get the answer.
Practice 3 Digit Addition without Regrouping
Do you need some practice pages for your students to use with this strategy?
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