Once the students have learned how to write equations (a) translating sentences into equations and (b) translating equations into sentences, the students will now solve one-step equations using addition and subtraction.
Common Core State Standards
A.REI.1: Explain each step in solving a simple equation as following from the equality of numbers asserted at the previous step, starting from the assumption that the original equation has a solution. Construct a viable argument to justify a solution method.
A.REI.3: Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters.
Mathematical Practice(s): 6. Attend to precision
- I can apply order of operations and inverse operations to solve equations
- I can construct an argument to justify my solution process
In what ways can the problem be solved and why should one method be chosen over another?
Vocabulary: inverse operation, isolate, variable, constant
LESSON - Solve by Adding
- Instruct that minus and negative are equivalent
- GOAL: to isolated the specified variable
- Instruct that what is done on one side of the equation (= sign), must be done on the other side of the = sign.
Problem: k – 16 = 12
Step 1: Identify the variable we are solving for: (k)
Step 2: To isolate that variable, you must do the inverse operation to get zero by the variable (cancel out). For example: if you have +6 by the variable, you would subtract 6 from both sides of the equation and vice versa.
K – 16 = 12
Step 3: Add or subtract (depending on your signs) your constants:
K – 16 = 12
K = 28 (-16 + 16 = 0, so you don’t have to write it)
Guided Practice: 3-6 practice problems. You can do 1or 2 problems with the students at the board (Smart Board, Elmo, etc.) and then put them in small groups of no more than 3 to do the rest. These problems can be pulled from any textbook or other resource.
- Go to www.thatquiz.org
- Click on algebra (under integers)
- Choose the length you want (10 is the minimum)
- Choose the level you want. Level 1 is simple one-step equations
- Check Solve (x) only
- This website can be used for many other topics also. Please browse this free website.
Independent Practice: 10-15 problems to be done alone. These problems can be pulled from any textbook or other resource.
Closure/Review: Ask 1-3 questions relating to today’s lesson to be answered by the class as a whole. This will give you a general idea of the class’ understanding of today’s topic.
Exit Ticket: This is to be done the last 3-5 minutes of class and given to you (by hand or in a designated area of your room) as they leave class. Possible questions:
- Define in your own words or provide an example of isolate, variable and constant.
- Solve x – 16 = 10.
- What is the inverse of +6?
This post is part of the series: Beginner Algebra
Make algebra easier for your students with these introductory lesson plans.
- Lesson Plan: Solving One-Step Equations using Addition or Subtraction
- Lesson Plan: Solving One-Step Equations using Multiplication or Division
- High School Math Lesson Plan: Solving Multi-Step Equations
- Lesson Plan: Solving Equations with Variables on Both Sides of the Equation
- Algebra Lesson Plan: Solving Absolute Value Equations