Math lesson plan · 2nd grade (Year 3 in England) · 45 minutes
Subtract two-digit numbers without regrouping
Addition and subtraction
CCSS 2.NBT.B.5England: Y2 Addition and subtraction
Objective and success criteria
Students will: Subtract two-digit numbers without 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: Subtract multiples of ten
Leads to: Subtract three-digit numbers without regrouping
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 multiples of ten). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Yuki had 30 cents and spent 10 cents. How many cents are left? → 20Prompt: Count back in tens.
- 50 − __ = 30 → 20Prompt: How many tens were taken away?
- Ravi had 30 cents and spent 10 cents. How many cents are left? → 20Prompt: Count back in tens.
Hook · 5 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Subtract two-digit numbers without 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: Grace has 48 marbles. Nia has 10 marbles. How many more marbles does Grace have than Nia?
- Step 1: 48 − 10 = 38
- Step 2: 38
- Answer: 38
- 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.
- Grace has 52 pencils. Kofi has 22 pencils. How many more pencils does Grace have than Kofi? → 30Prompt: 'How many more' asks for the difference.
- Check by adding: if 62 − 20 = 42, then 42 + 20 should be what? → 62Prompt: Adding back what you took away undoes the subtraction.
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.
- Check by adding: if 46 − 21 = 25, then 25 + 21 should be what? → 46Prompt: Adding back what you took away undoes the subtraction.
- Sofia had 84 stones. Sofia gave 43 to Nia. How many stones does Sofia have left? → 41Prompt: Sofia gives some away, so the amount gets smaller.
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 multiples of ten.
- 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 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