Math lesson plan · 2nd grade (Year 3 in England) · 45 minutes
Story problems to 100: joining and separating
Addition and subtraction
CCSS 2.OA.A.1England: Y2 Addition and subtractionEngland: Y3 Addition and subtraction
Objective and success criteria
Students will: Story problems to 100: joining and separating.
- 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 two-digit numbers with regrouping; Subtract 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 two-digit numbers with regrouping; Subtract two-digit numbers with regrouping). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- There are 55 balls in a box and 21 on the table. How many balls are there in all? → 76Prompt: Add the tens, then add the ones.
- Omar collected 23 crayons in the morning and 62 in the afternoon. How many is that altogether? → 85Prompt: Add the tens, then add the ones.
- Ben has 47 marbles. A friend gives Ben 42 more. How many marbles does Ben have now? → 89Prompt: Add the tens, then add the ones.
Hook · 5 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Story problems to 100: joining and separating. 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: Omar has 43 crayons. Chloe gives Omar 37 more. How many crayons does Omar have now?
- Step 1: 43 + 37 = 80
- Step 2: 80
- Answer: 80
- 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.
- There are 45 acorns on the table and 29 acorns in a box. How many acorns are there altogether? → 74Prompt: Altogether means put both groups together.
- Omar has 40 buttons. 20 are in a bag and the rest are on the floor. How many buttons are on the floor? → 20Prompt: The whole is 40. One part is 20.
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 26 marbles on the table and 16 marbles in a box. How many marbles are there altogether? → 42Prompt: Altogether means put both groups together.
- Felix had 62 stickers. Felix gave some to Diego. Now Felix has 14 left. How many stickers did Felix give away? → 48Prompt: Felix started with 62 and ended with 14.
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 two-digit numbers with 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