🇺🇸 CCSS Math · Grade 6

6.EE.B.7: Solving one-step equations

6.EE.B.7 explained: writing and solving x + p = q and px = q with nonnegative rational numbers, common errors, a worked example and free practice.

Common Core standard CCSS.Math.Content.6.EE.B.7

Solve real-world and mathematical problems by writing and solving equations of the form x + p = q and px = q for cases in which p, q and x are all nonnegative rational numbers.

Grade
Grade 6
Domain
Expressions & Equations (EE)
Cluster
Reason about and solve one-variable equations and inequalities

Official wording from the Common Core State Standards for Mathematics (© 2010 National Governors Association Center for Best Practices and Council of Chief State School Officers). View on thecorestandards.org

What 6.EE.B.7 means

Sixth graders write and solve equations of exactly two shapes: x + p = q and px = q, where every number involved, including the solution, is zero or positive. That restriction is deliberate. It lets students concentrate on what solving means, undoing an operation to find the unknown, before negative numbers and two-step equations arrive in seventh grade.

For x + p = q, subtracting p from both sides isolates x: if x + 4.5 = 11, then x = 6.5. For px = q, dividing both sides by p isolates x: if 3x = 7, then x = 7/3. The numbers can be fractions and decimals, so (2/3)x = 10 is fair game, and its solution is 15. Writing the equation from a word problem is half the task. A student who reads 'after spending $18 Ana has $27 left' should be able to write x - 18 = 27, or think of it as 27 + 18 = x, and explain why both describe the same situation.

Students should be able to

  • Write an equation of the form x + p = q or px = q for a word problem.
  • Solve these equations using inverse operations, keeping both sides balanced.
  • Solve equations whose numbers are fractions or decimals.
  • Check a solution by substituting it into the original equation.
  • Interpret the solution in the context of the problem.

Common misconceptions

Doing the same operation instead of the inverse

For x + 8 = 20 some students add 8 to both sides. Ask what undoes adding 8: subtracting 8.

Dividing the wrong way

For 4x = 10 students write x = 4/10. The x is multiplied by 4, so divide 10 by 4: x = 10/4 = 2.5.

Changing only one side

Subtracting from the left side and not the right breaks the balance. A hanger or scale model shows why both sides must change.

Worked example: fractional coefficient

Two thirds of a number of tickets have been sold, which is 10 tickets. Write and solve an equation for the total number of tickets.

  1. Let t = total number of tickets. Two thirds of t is 10, so (2/3)t = 10.
  2. Undo multiplying by 2/3 by dividing both sides by 2/3, which is the same as multiplying by 3/2.
  3. t = 10 × 3/2 = 30/2 = 15.
  4. Check: (2/3) × 15 = 10. True.

Answer: There are 15 tickets in total.

Teaching 6.EE.B.7

Balance pictures and tape diagrams help students see why the same operation is done to both sides. Encourage students to check every solution by substitution, which also links back to 6.EE.B.5.

Assessments pair equation-writing with solving, often in money, measurement and sharing contexts with decimal or fraction values. Students should be able to explain each step in words.

6 practice questions

Original questions written for this standard. Choose an option or type your answer, then press Check. Every question has a worked explanation.

Score: 0 / 6(0 of 6 checked)
  1. 1.

    Solve x + 4.5 = 11.

    Answer and explanation

    Answer: 6.5 (also accepted: x = 6.5)

    Subtract 4.5 from both sides: x = 11 - 4.5 = 6.5. Check: 6.5 + 4.5 = 11.

  2. 2.

    Solve 8y = 52.

    Answer and explanation

    Answer: 6.5 (also accepted: y = 6.5, 13/2)

    Divide both sides by 8: y = 52 ÷ 8 = 6.5. Check: 8 × 6.5 = 52.

  3. 3.

    Solve (3/4)m = 12.

    Question 3 options
    Answer and explanation

    Answer: B) 16

    Divide by 3/4, which means multiplying by 4/3: 12 × 4/3 = 16. Check: 3/4 of 16 is 12.

  4. 4.

    Ana spent $18 and has $27 left. Which equation can find how much she started with, x?

    Question 4 options
    Answer and explanation

    Answer: C) x - 18 = 27

    Starting amount minus what she spent equals what is left: x - 18 = 27, so x = 45.

  5. 5.

    A pack of 6 juice boxes costs $4.20. Solve 6c = 4.20 for the cost c of one box, in dollars.

    Answer and explanation

    Answer: 0.70 (also accepted: 0.7)

    Divide both sides by 6: c = 4.20 ÷ 6 = 0.70. Each box costs $0.70.

  6. 6.

    Solve n + 2/5 = 1.

    Answer and explanation

    Answer: 3/5 (also accepted: 0.6, n = 3/5)

    Subtract 2/5 from both sides: n = 1 - 2/5 = 3/5.

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FAQ

Which equations are in 6.EE.B.7?

Only one-step equations of the forms x + p = q and px = q, where p, q and x are nonnegative rational numbers. Two-step equations come in grade 7.

Can 6th grade equations have fraction answers?

Yes. Nonnegative rational numbers include fractions and decimals, so solutions like 7/3 or 6.5 are expected.

More grade 6 Expressions & Equations standards

6.EE.A.1: Whole-number exponents6.EE.A.2: Writing, reading and evaluating expressions6.EE.A.3: Generating equivalent expressions6.EE.A.4: Identifying equivalent expressions6.EE.B.5: Solutions of equations and inequalities6.EE.B.6: Using variables to represent numbers6.EE.B.8: Writing and graphing inequalities6.EE.C.9: Dependent and independent variables
All Grade 6 math standards →Standards home →