Math lesson plan · 2nd grade (Year 3 in England) · 30 minutes
Add two-digit numbers with regrouping
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: Add two-digit numbers with regrouping.
- 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: Add and subtract tens; Tens and ones
Leads to: Subtract two-digit numbers with regrouping; Add and subtract within 1000; Two-step addition and subtraction problems
Materials: Base-ten blocks, Number lines, Hundred square, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Add and subtract tens; Tens and ones). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 70 + 20 = ? → 90Prompt: Think in tens: 7 tens and 2 tens.
- 10 − 10 = ? → 0Prompt: Think in tens: 1 tens take away 1 tens.
- 10 + 70 = ? → 80Prompt: Think in tens: 1 tens and 7 tens.
Hook · 3 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Add two-digit numbers with regrouping. 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: Elena collected 18 crayons in the morning and 24 in the afternoon. How many is that altogether?
- Step 1: 10 + 20 = 30
- Step 2: 8 + 4 = 12
- Step 3: 30 + 12 = 42
- Answer: 42
- 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.
- Hiro collected 42 marbles in the morning and 15 in the afternoon. How many is that altogether? → 57Prompt: Add the tens, then add the ones.
- 37 + 19 + 17 = ? → 73Prompt: Add two numbers first, then add the third.
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.
- 39 + 18 + 14 = ? → 71Prompt: Add two numbers first, then add the third.
- There are 30 cookies in a box and 52 on the table. How many cookies are there in all? → 82Prompt: Add the tens, then add the ones.
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: Add and subtract tens.
- 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: Subtract two-digit numbers with regrouping; Add and subtract within 1000; Two-step addition and subtraction problems.
- 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