Math lesson plan · 2nd grade (Year 3 in England) · 30 minutes
Add and subtract whole hundreds
Addition and subtraction
CCSS 2.NBT.B.7CCSS 2.NBT.B.8England: Y2 Addition and subtractionEngland: Y3 Addition and subtraction
Objective and success criteria
Students will: Add and subtract whole hundreds.
- 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; Hundreds, tens and ones
Leads to: Add three-digit numbers without regrouping; Subtract three-digit numbers without regrouping
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; Hundreds, tens and ones). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 40 − 20 = ? → 20Prompt: Think in tens: 4 tens take away 2 tens.
- 80 − 40 = ? → 40Prompt: Think in tens: 8 tens take away 4 tens.
- 40 − 30 = ? → 10Prompt: Think in tens: 4 tens take away 3 tens.
Hook · 3 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Add and subtract whole hundreds. 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: 900 − 300 = ?
- Step 1: 9 − 3 = 6
- Step 2: 900 − 300 = 600
- Answer: 600
- 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.
- 200 + 100 = ? → 300Prompt: Think in hundreds: 2 + 1.
- 184 + 100 = ? → 284Prompt: Only the hundreds digit changes.
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.
- A school has 300 pencils and buys 100 more. Zoe hands out 100. How many pencils are left? → 300Prompt: First add, then subtract.
- 357 + 300 = ? → 657Prompt: Only the hundreds digit changes.
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: Add three-digit numbers without regrouping; Subtract three-digit numbers without regrouping.
- 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