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Common Core Math6th GradeExpressions & Equations

6.EE.6: Write Expressions with Variables

Also written as 6.EE.B.6 and CCSS.MATH.CONTENT.6.EE.B.6 · Cluster: Reason about and solve one-variable equations and inequalities.

Make 6.EE.6 Word ProblemsAll 29 6th Grade Math Standards

The Official Wording

Use variables to represent numbers and write expressions when solving a real-world or mathematical problem; understand that a variable can represent an unknown number, or, depending on the purpose at hand, any number in a specified set.

Common Core State Standards, Grade 6, Expressions & Equations · Read it at the source · Checked October 14, 2026

What 6.EE.6 Means in Plain English

Sixth graders choose a letter for a number they do not know, or one that changes, and build an expression around it. Tickets cost $8 and a group buys n: the cost is 8n. Ava is 3 years older than her brother, aged b: she is b + 3.

In 8n the letter stands for any number of tickets, and in b + 3 it is one unknown age waiting to be found. Both come before 6.EE.7 solves for the unknown, and 7th graders write the same kind of expression for two-step problems (7.EE.4).

6.EE.6 I Can Statements

  • I can pick a letter to stand for an unknown number.
  • I can write an expression like 8n for a real situation.
  • I can say whether my variable is one unknown or any number.

6.EE.6 Worked Example

A field-trip budget with one number nobody knows yet, written as an expression before anyone reaches for an answer.

Problem

A bus costs $150 to rent, and the museum charges $6 per student. Write an expression for the total cost of the trip.

Writing an expression for the field-trip cost
  1. Find the number that is not fixed. The bus is $150 no matter what. The number of students is the unknown, so give it a letter.Let s = the number of students
  2. Translate the per-student charge. $6 for each of s students is 6 × s, written 6s.6s
  3. The bus is added once, whatever s is.6s + 150
  4. Make the expression do a real job: it gives the cost for any class size.s = 25: 6(25) + 150 = 300
AnswerTotal cost = 6s + 150, where s is the number of students

Check it: Try s = 30 by reasoning and by the expression: 30 students at $6 is $180, plus the $150 bus is $330, and 6(30) + 150 = 330.

Common Mistakes with 6.EE.6

Writing a number instead of a letter

“The cost is 6 × 25 + 150” when the class size was never given

Try this: Ask “do we know that number?” If not, a letter holds its place: 6s + 150 works for every class size.

Letting the letter stand for the object

“s = students” and then 6s read as “6 students”

Try this: Define the variable as a number every time: s is the number of students, so 6s is the dollars they pay.

Multiplying the fixed cost too

Total = (6 + 150)s = 156s

Try this: Act it out with two class sizes: the bus is paid once, not once per student, so the 150 stands alone.

Where 6.EE.6 Fits

Comes Before5.OA.2Write simple expressions that record calculations with numbers.6.EE.2Write expressions like 5 - y and read their parts.
Alongside6.EE.5Decide by substitution whether a number is a solution.6.RP.3Use ratio and rate reasoning to solve real-world problems.
Comes Next6.EE.7Write and solve one-step equations like 6s = 180.6.EE.9Let two variables change together and write d = 65t.7.EE.4Write and solve two-step equations like 6s + 150 = 330.

Practice 6.EE.6

Word Problem GeneratorFree ToolSituations with one unknown and one fixed number, the raw material for writing 6s + 150 before anyone solves anything.Write an expressionOne unknownGrade 6
Make Word Problems
Math Worksheet GeneratorFree ToolPhrase-to-expression translation sets: “twice a number, less 7” and the like, with an answer key.Translate phrasesVariablesAnswer key
Make a Worksheet

Quick Check

  1. A pencil costs 40 cents. Write an expression for the cost of p pencils in cents.
  2. Leo has 12 more stickers than Mia. If Mia has m stickers, how many does Leo have?
  3. A plumber charges $45 to visit plus $30 per hour. Write an expression for a job that takes h hours, then find the cost of a 3-hour job.

6.EE.6: Other Names

6.EE.66.EE.B.6CCSS.MATH.CONTENT.6.EE.B.6

Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved. Official wording from the Common Core State Standards PDFs at corestandards.org, last checked October 14, 2026. The explanation, I can statements, example, mistakes and practice on this page are EMStudio’s own, written beside the official wording. They are not part of the standard.