Math lesson plan · 2nd grade (Year 3 in England) · 45 minutes
Add three-digit numbers with regrouping
Addition and subtraction
CCSS 2.NBT.B.7CCSS 2.NBT.B.9England: Y3 Addition and subtraction
Objective and success criteria
Students will: Add three-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 three-digit numbers without regrouping; Add two-digit numbers with regrouping
Leads to: the next skill in this area.
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 (Add three-digit numbers without regrouping; Add two-digit numbers with regrouping). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- There are 655 crayons on the table and 210 crayons in a box. How many crayons are there altogether? → 865Prompt: Altogether means put both groups together.
- There are 378 shells on the table and 520 shells in a box. How many shells are there altogether? → 898Prompt: Altogether means put both groups together.
- Priya has 200 beads. Ava has 481 more beads than Priya. How many beads does Ava have? → 681Prompt: Who has more, Priya or Ava?
Hook · 5 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Add three-digit numbers with regrouping. 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: 377 + 186 = ?
- Step 1: Ones: 7 + 6 = 13 → write 3, carry 1 ten
- Step 2: Tens: 7 + 8 + 1 = 16 → write 6, carry 1 hundred
- Step 3: Hundreds: 3 + 1 + 1 = 5
- Step 4: 377 + 186 = 563
- Answer: 563
- 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.
- 165 + 143 = ? → 308Prompt: Add the ones first. If they make 10 or more, carry a ten.
- There are 204 shells on the table and 476 shells in a box. How many shells are there altogether? → 680Prompt: Altogether means put both groups together.
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.
- There are 284 pencils on the table and 321 pencils in a box. How many pencils are there altogether? → 605Prompt: Altogether means put both groups together.
- 558 + 183 = ? → 741Prompt: Add the ones first. If they make 10 or more, carry a ten.
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 three-digit numbers without regrouping.
- 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
- 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