Math lesson plan · 6th grade (Year 7 in England) · 30 minutes
Evaluate expressions
Algebra
CCSS 6.EE.A.2.CEngland: Y6 AlgebraEngland: KS3 Algebra
Objective and success criteria
Students will: Evaluate expressions.
- 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: Write algebraic expressions; Whole-number exponents
Leads to: One-step equations; Dependent and independent variables; Graphs of linear equations y = mx + b
Materials: Balance scales or a balance drawing, Algebra tiles, Function machine cards, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Write algebraic expressions; Whole-number exponents). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Which expression means "3 less than n"? (3n / n + 3 / n − 3 / 3 − n) → n − 3Prompt: Translate the words in order, carefully.
- Evaluate 2⁶. → 64Prompt: Write it out: 2 × 2 × 2 × 2 × 2 × 2
- Write an expression for: 1 added to 5 times a number n. → 5n+1Prompt: '5 times n' is written 5n.
Hook · 3 min
- Show a "think of a number" puzzle and ask the class to work out the starting number.
- Share the objective: Evaluate expressions. Read the success criteria together.
I do: model it · 7 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Find the value of 8x + 6 when x = 2.
- Step 1: 8 × 2 + 6
- Step 2: = 16 + 6 = 22
- Answer: 22
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 6 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Find the value of 2x − 1 when x = 9. → 17Prompt: Replace x with 9.
- Evaluate x² + 2y when x = 4 and y = −1. → 14Prompt: Substitute each letter, using brackets around negative numbers.
You do: independent practice · 7 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 6 questions are on the student sheet below, with answers in the key.
Exit ticket · 3 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Evaluate x² + 4y when x = −3 and y = −1. → 5Prompt: Substitute each letter, using brackets around negative numbers.
- Convert 80 °C to °F using F = 9C/5 + 32. → 176Prompt: Multiply C by 9, divide by 5, then add 32.
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: Write algebraic expressions.
- 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: One-step equations; Dependent and independent variables; Graphs of linear equations y = mx + b.
- 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-6.
Free lesson plan from eurekami.com/lesson-plan-builder