Math lesson plan · 2nd grade (Year 3 in England) · 45 minutes
Find a difference by counting up
Addition and subtraction
CCSS 2.NBT.B.5CCSS 2.NBT.B.9England: Y2 Addition and subtractionEngland: Y3 Addition and subtraction
Objective and success criteria
Students will: Find a difference by counting up.
- 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: Subtract by thinking of an addition; Add tens to a two-digit number
Leads to: Find the missing number in additions and subtractions to 100
Materials: Base-ten blocks, Number lines, Hundred square, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Subtract by thinking of an addition; Add tens to a two-digit number). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 4 + 4 = 8. Use this to find 8 − 4. → 4Prompt: 4 and what make 8?
- To work out 10 − 3, think: 3 + __ = 10 → 7Prompt: Count up from 3 to 10.
- 3 + 3 = 6. Use this to find 6 − 3. → 3Prompt: 3 and what make 6?
Hook · 5 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Find a difference by counting up. 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: 59 − 53 = ?
- Step 1: 53 + 6 = 59
- Step 2: 6
- Answer: 6
- 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.
- 74 − 68 = ? → 6Prompt: The numbers are close together.
- Priya has scored 42 points in a game. The target is 69. How many more points are needed? → 27Prompt: 42 + ? = 69
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.
- 63 − 55 = ? → 8Prompt: The numbers are close together.
- Hiro has scored 54 points in a game. The target is 81. How many more points are needed? → 27Prompt: 54 + ? = 81
Watch out for
- Subtracting the smaller digit from the bigger one in every column (52 − 17 = 45).
- Forgetting to add the regrouped (carried) ten.
Support and stretch
Support
- Review first: Subtract by thinking of an addition.
- Use concrete materials: base-ten blocks.
- 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: Find the missing number in additions and subtractions to 100.
- 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-2.
Free lesson plan from eurekami.com/lesson-plan-builder