When your students first start evaluating expressions, it can feel overwhelming. They’re juggling substitution, order of operations, and understanding what variables and constants actually represent. All at once! Breaking the process down step-by-step is key to helping your students feel more confident. If you’re preparing to introduce evaluating expressions in your classroom, I’ve got a clear, student-friendly approach to help you get started.
Watch the Video for a Step-by-Step Breakdown
Start by checking out this quick video that walks you through how to teach evaluating expressions clearly and effectively.
In the video, I show how to substitute values into expressions, review how order of operations applies, and highlight common mistakes students make when they first start. It’s perfect for 6th grade math teachers, long-term subs, or anyone needing a quick refresher on evaluating algebraic expressions.
Key Ideas to Emphasize When Evaluating Expressions
When teaching your students how to approach evaluating expressions, it’s important to share a few key ideas. First, your students should always start with substitution. They need to substitute the given value into the expression wherever the variable appears. This simple first step helps set them up for success before moving on to solving.
Then, you want to remind your students that the order of operations still matters. Even after substitution, they must carefully follow PEMDAS or GEMDAS, especially when the expression includes exponents or multiple operations. Taking a moment to double-check the order can prevent many simple mistakes.
Another important point is recognizing coefficients. When a number and a variable are written side-by-side, like in 3n, it means multiplication. Your students may fixate on this for a bit, but yes, it mean multiply even though no multiplication sign is shown. Take time to practice with your students because they need to think “3 times n” in these cases automatically.
You’ll want to watch out for one of the most common mistakes your students may make when evaluating expressions. That is treating substitution as replacement without multiplication. For example, instead of correctly multiplying in 3n, your student might mistakenly read it as 33 if n = 3.
Let’s look at an example. If the expression is 3n – 6 and n = 3, your students should substitute and rewrite the expression as 3 × 3 – 6, not as 33 – 6. Understanding this difference early makes a big difference as your students move into more complex expressions.
Tips for Helping Students With Evaluating Expressions
Evaluating expressions becomes much easier when your students get lots of guided practice early on. One simple but powerful trick is to have your students physically circle or box where the substitution needs to happen before solving. This visual cue helps them remember where they are placing values and encourages a more careful approach.
You can also encourage your students to rewrite the expression after substitution before they begin solving. For example, if x = 8, turn 64 ÷ x into 64 ÷ 8 before finding the final answer. This slows them down just enough to prevent careless mistakes. Also, practice highlighting the difference between constants (fixed values) and variables (changing values) to strengthen their understanding of the structure of an expression, not just how to solve it.
Additional Resources for Practicing Evaluating Expressions
If you’re looking for a resource that walks your students through evaluating expressions step-by-step, the Evaluating Expressions 6th Grade Math Notes, Practice, and Exit Tickets resource is the perfect fit!
This resource includes both print and digital options, making it flexible for any classroom setup. Here’s a peek at what’s inside:
- A fold-it-up vocabulary activity to introduce key terms like variable, constant, coefficient, and expression
- A lesson page with guided notes and six practice problems, plus three “You Try It” problems and an explanation prompt
- A practice page with 16 additional problems for independent reinforcement
- Exit tickets that can be used at the end of a lesson or the start of the next day for quick checks on understanding
- Teacher answer keys for every page
- Google Slides version of the notes and practice pages
- Google Forms version of the exit tickets for easy digital assessment
This resource is a great way to reinforce substitution skills and strengthen your students’ understanding of constants versus variables. It also gives them structured practice solving expressions using the order of operations. It’s aligned to 6th grade CCSS standards, so you can be confident it fits right into your math curriculum.
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