Math lesson plan · 1st grade (Year 2 in England) · 45 minutes
Word problems within 20
Addition and subtraction
CCSS 1.OA.A.1CCSS 1.OA.A.2England: Y1 Addition and subtraction
Objective and success criteria
Students will: Word problems within 20.
- 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 within 20; Subtract within 20
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 within 20; Subtract within 20). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Nia collected 9 cards in the morning and 6 in the afternoon. How many is that altogether? → 15Prompt: Do we join the groups or take away?
- There are 9 cookies in a box and 3 on the table. How many cookies are there in all? → 12Prompt: Do we join the groups or take away?
- Nia has 11 marbles. A friend gives Nia 4 more. How many marbles does Nia have now? → 15Prompt: Do we join the groups or take away?
Hook · 5 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Word problems within 20. 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: Elena had some books. After getting 5 more, Elena has 11. How many books did Elena have at first?
- Step 1: 11 − 5 = 6
- Answer: 6
- 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.
- Hiro had some books. After getting 12 more, Hiro has 19. How many books did Hiro have at first? → 7Prompt: We know the end amount and how many were added.
- At the pond Sam sees 5 ducks, 3 frogs and 6 fish. How many animals is that? → 14Prompt: Add all three numbers.
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.
- At the pond Omar sees 4 ducks, 5 frogs and 2 fish. How many animals is that? → 11Prompt: Add all three numbers.
- Yuki scored 12 points. Ben scored 3 points. How many fewer points did Ben score? → 9Prompt: 'How many fewer' means find the difference.
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 within 20.
- 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-1.
Free lesson plan from eurekami.com/lesson-plan-builder