CCSS.Math.Content.HSA-CED.A.1
The Standard
Create equations and inequalities in one variable and use them to solve problems. Include equations arising from linear and quadratic functions, and simple rational and exponential functions.
Common Core State Standards for Mathematics
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students define one unknown and translate a situation into an equation or inequality. They solve linear, quadratic, simple rational, or exponential models and interpret the answer in context.
What Mastery Looks Like
- Given a situation, the student defines one variable and writes a matching equation or inequality. They solve accurately, check the result, and reject values that do not make sense in the situation.
Common Misconceptions
- Students may choose an equation when the situation gives a limit and needs an inequality. They may treat exponential growth as repeated addition or forget restrictions on rational expressions. They may also keep quadratic solutions that do not fit the context.
How to Assess It
- Exit ticket: An account starts with $200 and grows 5% each year. Write and solve an equation to find when the balance reaches $255.25.
Lesson moves
Ways to Teach It
Use algebra tiles to build a rectangle with area 48 and side difference 2, then write and solve the quadratic.
Students explain when a budget limit needs an inequality instead of an equation, then write an example and defend their symbol.
Run a card match with situation, equation, and solution cards for linear, quadratic, rational, and exponential examples.
Give a phone plan charging $25 plus $8 per gigabyte, then have students write an inequality for a $65 budget.
Free download
Printable HSA-CED.A.1 Worksheet
A ready-to-print activity worksheet aligned to CCSS.Math.Content.HSA-CED.A.1, with an answer key for the teacher on its own page. No account needed.
PDF, US Letter, prints cleanly in black and white.
Download the worksheetLearning progression
Where This Standard Sits
Before This Standard
If students are struggling here, check these first.
- CCSS.Math.Content.7.EE.B.4
Students must already represent quantities with variables and form basic equations or inequalities before modeling harder one-variable situations.
- CCSS.Math.Content.8.EE.C.7
Solving one-variable linear equations supports using created equations to find unknowns before extending to quadratic, rational, and exponential cases.
- CCSS.Math.Content.HSA-SSE.A.1
Interpreting contextual expressions supports choosing variables, operations, and constraints when writing equations or inequalities from word problems.
What This Unlocks
Mastery here sets students up for these next.
Keep exploring
Related Standards
- CCSS.Math.Content.HSA-REI.B
Solve equations and inequalities in one variable
- CCSS.Math.Content.7.EE.B
Solve real-life and mathematical problems using numerical and algebraic expressions and equations.
- CCSS.Math.Content.6.EE.B
Reason about and solve one-variable equations and inequalities.
- CCSS.Math.Content.HSA-REI.B.3
Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters.
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