Math lesson plan · 7th grade (Year 8 in England) · 45 minutes
Expand brackets with a negative multiplier
Algebra
CCSS 7.EE.A.1England: KS3 AlgebraEngland: GCSE Foundation Algebra
Objective and success criteria
Students will: Expand brackets with a negative multiplier.
- 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: Expand brackets (distributive property); Multiply integers, including three factors and powers
Leads to: Expand two brackets and simplify; Solve equations with brackets and x on both sides
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 (Expand brackets (distributive property); Multiply integers, including three factors and powers). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Expand: 9(x − 8) → 9x-72Prompt: Multiply every term inside the bracket by the number outside.
- −12 × 9 = ? → -108Prompt: Multiply the sizes first.
- Expand: −6(3x + 4) → -18x-24Prompt: The negative outside multiplies every term inside.
Hook · 5 min
- Show a "think of a number" puzzle and ask the class to work out the starting number.
- Share the objective: Expand brackets with a negative multiplier. 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: Expand −5(x − 8).
- Step 1: −5 × x = −5x
- Step 2: −5 × (−8) = 40
- Step 3: −5x + 40
- Answer: -5x+40
- 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.
- Expand −7(x + 4). → -7x-28Prompt: Multiply BOTH terms by −7.
- Expand −(6x + 7). → -6x-7Prompt: A minus sign in front of brackets means × (−1).
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.
- Expand −7(x − 8). → -7x+56Prompt: Multiply BOTH terms by −7.
- Aisha expands −6(4x − 4) and gets −24x − 24. What is the correct expansion? → -24x+24Prompt: Check the second term: what is a negative times a negative?
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: Expand brackets (distributive property).
- 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: Expand two brackets and simplify; Solve equations with brackets and x on both sides.
- 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