Undo It! Solving Two-Step Equations

About This Resource

A complete Grade 6 math pack on solving two-step equations such as 3x + 5 = 26. Students use balance models and inverse operations to undo addition or subtraction first and multiplication second, check solutions by substituting, write equations for word problems and spot common mistakes. Includes slides with worked examples, a lesson plan, worksheet, quiz, homework, flashcards, a rubric and answer keys.

Overview

A two-step equation needs two inverse operations to find the unknown. In 3x + 5 = 26, the variable x has been multiplied by 3 and then 5 has been added. To solve it, we undo the steps in reverse order: subtract 5 from both sides (3x = 21), then divide both sides by 3 (x = 7). A balance model shows why we must do the same to both sides. Students solve equations with addition and subtraction, check every answer by substituting it back, translate word problems into equations (A plant is 4 cm tall and grows 2 cm a week…) and find the error in worked solutions.

Resource Details

Subject: Math
Topic: Two-Step Equations
Category: Problem Solving
File Type: PDF
File Size: 274 KB
Published: 13 Nov 2026
Downloads: 0

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Grade 6 math (ages 11–12) 55 minutes Algebra inverse operations problem solving checking

Learning Objectives

Solve two-step equations using inverse operations in the correct order.
Check a solution by substituting it into the equation.
Write and solve two-step equations for word problems.

How to Use This Resource

Start with the slides: a balance with 3 bags of marbles and 5 loose marbles on one side and 26 marbles on the other. Ask: "How many marbles are in each bag?"
Teach the two steps with the worked examples, then do worksheet activities 1 and 2 together.
Students complete activities 3 to 6, then use the quiz and send the homework page home.

Classroom Activity Ideas

Balance puzzles: students draw balances for equations and remove the same amount from both sides.
Think of a number: I think of a number, multiply by 4 and add 3. I get 31. What was my number?
Error hunt: groups find and correct mistakes in worked solutions.

Differentiation

Support: give a two-row table (undo +/−, then undo ×/÷) and keep answers under 10. Challenge: students solve equations with the variable on both sides or with negative solutions.

Assessment

Use the worksheet and quiz to check solving and checking. Use the rubric to assess word problems and explanations.

Teacher Tips

Students often divide first (3x + 5 = 26 → x + 5 = 26 ÷ 3). Remind them to undo the last operation first, like taking off your shoes before your socks. Insist on substituting the answer to check.

What's Included

10-page printable PDF lesson pack: teacher lesson plan with timings, materials and differentiation
Key vocabulary list (6 words with meanings and examples)
Student worksheet (6 activities)
Quiz / assessment (3 parts)
Homework practice page
Printable flashcards: 6 A5 picture cards (separate PDF)
Assessment rubric (4 levels)
Lesson slides (editable PowerPoint)
Editable Word version of all student pages
Complete answer key (also as a separate PDF)