Math lesson plan · 3rd grade (Year 4 in England) · 45 minutes
Find the rule of a number pattern
Algebra
CCSS 3.OA.D.9England: Y3 Number and place value
Objective and success criteria
Students will: Find the rule of a number pattern.
- 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: Number patterns
Leads to: Generate a pattern from a rule and predict later terms
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 (Number patterns). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- What comes next? 29, 36, 43, 50, __ → 57Prompt: How much does the pattern go up each time?
- Find the missing number: 102, 99, 96, __, 90 → 93Prompt: Is the pattern going up or down? By how much?
- What is the rule for this pattern? 20, 15, 10, 5 (Add 5 / Double / Add 6 / Subtract 5) → Subtract 5Prompt: Look at how you get from each number to the next.
Hook · 5 min
- Show a "think of a number" puzzle and ask the class to work out the starting number.
- Share the objective: Find the rule of a number pattern. 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: What is the rule? 84, 77, 70, 63, 56, …
- Step 1: 77 − 84 = -7
- Step 2: subtract 7
- Answer: subtract 7
- 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.
- What is the rule? 14, 39, 64, 89, 114, … (subtract 25 / multiply by 25 / add 25 / add 26) → add 25Prompt: Find the difference between neighbouring numbers.
- The rule is "add 5". One number is wrong: 15, 20, 25, 31, 35. What should it be? → 30Prompt: Check each jump: is it exactly 5?
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.
- Look at the 3 times table: 3, 6, 9, 12, 15, … Are all the answers odd, all even, or a mix? (all even / all odd / a mix) → a mixPrompt: Is 3 odd or even?
- The rule is "add 6". One number is wrong: 8, 15, 20, 26, 32. What should it be? → 14Prompt: Check each jump: is it exactly 6?
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: Number patterns.
- 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: Generate a pattern from a rule and predict later terms.
- 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-3.
Free lesson plan from eurekami.com/lesson-plan-builder