Breaking apart an addend is a mental math strategy for addition. Some students may find this method more efficient than left-to-right addition.
This strategy involves breaking up one addend in an equation into more manageable parts. Like many other mental math strategies, this strategy encourages students to think flexibly and to manipulate numbers in different ways. This is the big goal of mental math!
As you look at the examples given, you’ll notice that this strategy reinforces place value understanding, as students are breaking apart the addend by place value.
Let’s take a look at how to perform this strategy. Whenever you introduce a new strategy in your classroom, be sure to use small, easy to work with numbers. This will ensure that students can focus on the strategy itself rather than struggling with big numbers while trying to master a new strategy.
In this example, we will add 14+12. We will break the 12 into a 10 and a 2.
Now we add. First we add 14+10 to make 24, and then add the remaining 2 to make 26.
Let’s try another example. Here we will solve 35+46. First we break the 46 into a 40 and a 6.
We will add 35+40 to make 75, and then add the remaining 6 to make 81.
One of the greatest aspects of mental math is that there is not a series of steps to memorize. Really we just want our students to understand what the numbers mean and be able to manipulate them in a way that works for each individual student.
Suppose we have the equation 213+214.
One student might choose to break up the second number and add 213+200+10+4.
Another student might choose to break up the second number into only two parts and add 200+210+4.
A third student might choose to add these numbers using left to right addition.
Here’s a video with more information on how you can teach the break apart strategy using the Concrete Representational Abstract model:
This is one strategy that you definitely will want to incorporate into your math instruction. It can be used in many different ways and you will notice that your students begin using this sort of thinking for other math concepts as well.
- If you would like full support for teaching this strategy, find my Break Apart for Addition Unit HERE.
- Download a FREE activity for practicing the breaking up an addend HERE.