Of all the word problem types, join problems are the ones students usually meet first — and for good reason. They involve combining quantities, which is a concept most kids already understand before you name it.
But even though join problems are generally the most accessible problem type, they’re worth teaching deliberately. The routine you build here — consistent vocabulary, labeling, numberless problems first — is the same routine that carries students into trickier problem types later on. Getting it right with join problems makes everything else easier.
Below is a video I recorded walking through how I teach join word problems. The text below covers the highlights, but the video goes into more depth.
Three Types of Join Word Problems
There are three types of join problems. I go in depth on them in the video and in this post, focusing on using keywords to solve word problems.
Here are three examples of join problems across the three join problem types. These differ from the word problems in the video.
JRU (Join Result Unknown)
There were _____ kids on the playground. ____ more kids came onto the playground. How many kids are on the playground?
JCU (Join Change Unknown)
There were ____ kids on the playground. Some more kids came on the playground. Now there are ____ kids on the playground. How many kids came on the playground?
JSU (Join Start Unknown)
Some kids were on the playground. ____ kids came on the playground. Now there are ____ kids on the playground. How many kids were on the playground at the beginning?
Teaching Join Word Problems
I follow a few routines when I teach word problems to students. One key is being consistent with the vocabulary and routine.
Use Consistent Vocabulary when Teaching Join Word Problems
When teaching join word problems, I consistently use the same three words to label and talk about them. These are also the same words I use when teaching separate word problems. Once students learn them for join word problems, they can easily see the relationship between join and separate word problems.
What are those three words? They are start, change, and result.
- The start is where the problem begins — the initial quantity before anything happens.
- The change is what changes within the word problem. What gets added to or taken from the person or object in the problem.
- The result is not the answer; rather, it is the result of the change.
Be careful when using the word result and be sure not to indicate an “answer” in the problem. The result is only the answer when it is the unknown.
Solve for an Unknown, Not the Answer
Another key part of the routine is to always solve for the unknown. The unknown can be any of the three: start, change, or result, and how a student solves the problem depends on where the unknown is placed.
I consistently use a box for the unknown. As I walk through the problem, I will label the start, change, and result and use a box for whatever is unknown. That is what students need to find.
Label the word problem using consistent vocabulary
As I walk through the word problem with students, I label it with an S, C, and R to signify the start, change, and result. This labeling also helps keep the vocabulary consistent.
Write an equation that matches the Join Word Problem
As we work through understanding the problem, we write an equation. Up until this point, students don’t have any numbers in the problem. You can find out why I don’t include numbers in word problems in this blog post.
Finally, Give Students the Numbers
At this point, give students the problem numbers.
Since there are blank spaces, you can easily differentiate the numbers in the problem. I developed this resource for my first- and second-grade combination classroom. I could easily give both grade levels the same problem and differentiate the numbers for each grade level.
Be sure to check the result and make sure it’s more than the start or the change.
It can feel like a lot of front-end work before students actually solve anything. But the consistency pays off—once students internalize the start/change/result structure for join problems, they apply it to separate problems, compare problems, and eventually multi-step problems without relearning the routine from scratch.
Video for Join Problems
In the videos below, I walk through each of the three join problem types and model how I use a number line to solve them.
Free Word Problems by Problem Type including Join Problems
Do you want a free sample of the word problems I use in my classroom?
Word Problems Teaching Resources for Your Classroom
Are you teaching word problems and need more resources to meet the needs of all your learners? Check out these word problem resources for your classroom.
Course
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How to Teach Word Problems by Problem Type
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Hi Jessica! I am a homeschool grandma and I absolutely LOVE the way you explain word problems. Thank you!
What advice do you have for helping students identify the CHANGE in word problems?
This blog post might help: https://whatihavelearnedteaching.com/teach-your-students-to-solve-word-problems/
Basically, I have students look for the action in the problem (something was dropped, put into a shopping cart, erased, etc.). That action is the change.
Hello! Could you please tell me where I can find your Models and Strategies for 2 digit addition?
Yep! It’s here: https://whatihavelearnedteaching.com/models-strategies-for-two-digit-addition-subtraction/
I am a homeschooling mom. I have been using your addition and subtraction word problems for the last 2 years! Your way of teaching word problems works great! Do you have any teaching strategies for multiplication and division word problems? Thank you!
That’s awesome! I’m so glad that it’s working for you! I have a resource for Multiplication & Division here: https://whatihavelearnedteaching.com/product/multiplication-division-word-problems/. I do not have a blog post series for it. Many of the teaching methods will be similar to addition and subtraction. The strategies your child uses will be different. I do have a course for word problems here: https://premium.whatihavelearnedteaching.com/word-problems-course/. The course has all four operations and goes more in-depth about the strategies students could use when solving various problem types.
How can you teach join problems to a child with dyslexia? My son struggles with identifying the change. Any helpful tips or advice?
Yes! You can. The video gives a lot of good tips that I would also use with dyslexic students. Reading word problems is about reading comprehension, not about phonics and decoding. If a student is struggling to read the problem, I would read it aloud to them to make sure that decoding the words wasn’t the barrier.