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7th grade · Math · Unit 4 of 15

Two-Step Equations

Undo, undo, solve for x

What your child practices

Solving equations like 3x + 5 = 26 by undoing each step on both sides, writing equations from word problems and checking solutions.

Minnesota K-12 Academic Standards benchmark: 7.3.6.2 · writing and solving two-step equations

How we explain it

Children can open this short lesson before they practice.

  1. Keep the equation balanced: do the same to both sides.
  2. Undo the adding or subtracting first.
  3. Then undo the multiplying or dividing.

Example: 2x + 3 = 11 Subtract 3 from both sides: 2x = 8. Divide both sides by 2: x = 4. Answer: x = 4

Two-Step Equations in Minnesota

In the Minnesota K-12 Academic Standards, this is unit 4 of 15 in 7th grade Math, after Fractions, Decimals & Percents and before Circles.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: Minnesota Department of Education (MDE)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    On a balance scale, 8 identical bags of marbles plus 18 loose marbles balance 114 loose marbles. How many marbles are in each bag?

    ⚖️8x + 18 = 114

    answer box

  2. Question 2

    Solve: 9n − 10 = 26

    • 3
    • 4
    • 36
    • 5

  3. Question 3

    Zoe has $29 saved and adds $8 each week. After how many weeks will Zoe have $53?

    answer box

  4. Question 4

    Solving 6x + 2 = 20, you reach 6x = 18. Which step gets x by itself?

    • Divide both sides by 6
    • Subtract 6 from both sides
    • Multiply both sides by 6
    • Divide only the left side by 6

  5. Question 5

    Is x = 8 a solution of 3x − 23 = 1?

    3x − 23 = 1

    • No
    • Yes

  6. Question 6

    Which equation matches this sentence? "Five times a number, plus 3, equals 28."

    • 5n + 3 = 28
    • 3n + 5 = 28
    • 5n − 3 = 28
    • 5(n + 3) = 28

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