Math lesson plan · 7th grade (Year 8 in England) · 45 minutes
Solve one-step inequalities, including dividing by a negative
Algebra
CCSS 7.EE.B.4.BEngland: KS3 AlgebraEngland: GCSE Foundation Algebra
Objective and success criteria
Students will: Solve one-step inequalities, including dividing by a negative.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Inequalities: meaning and solutions; Divide integers and find missing factors
Leads to: Solve two-step inequalities
Materials: Balance scales or a balance drawing, Algebra tiles, Function machine cards, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Inequalities: meaning and solutions; Divide integers and find missing factors). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- −33 ÷ 11 = ? → -3Prompt: Divide the sizes.
- Which inequality matches? "More than 18 people came to the concert." (x is the amount) (x > 18 / x < 18 / x ≥ 18 / x ≤ 18) → x > 18Prompt: 'At least' means that number or more.
- −6 ÷ 1 = ? → -6Prompt: Divide the sizes.
Hook · 5 min
- Show a "think of a number" puzzle and ask the class to work out the starting number.
- Share the objective: Solve one-step inequalities, including dividing by a negative. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Solve: x + 6 ≤ 2
- Step 1: x ≤ −4
- Answer: x ≤ −4
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Solve: x + (−3) < 8 → x < 11Prompt: Solve it like an equation.
- Solve: −2x < −12 → x > 6Prompt: Divide both sides by −2.
You do: independent practice · 10 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Solve: x + 11 ≥ 21 → x ≥ 10Prompt: Solve it like an equation.
- Solve: x / (−5) ≥ 1 → x ≤ −5Prompt: Multiply both sides by −5.
Watch out for
- Doing an operation to one side of an equation but not the other.
- Reading 3x as 3 + x, or thinking x always stands for one particular number.
Support and stretch
Support
- Review first: Inequalities: meaning and solutions.
- Use concrete materials: balance scales or a balance drawing.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Solve two-step inequalities.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-7.
Free lesson plan from eurekami.com/lesson-plan-builder