Math lesson plan · 1st grade (Year 2 in England) · 30 minutes
Add a one-digit number to a two-digit number (making a new ten)
Addition and subtraction
CCSS 1.NBT.C.4England: Y2 Addition and subtraction
Objective and success criteria
Students will: Add a one-digit number to a two-digit number (making a new ten).
- 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 a one-digit number to a two-digit number (no new ten); Add by making a ten first
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 · 4 min
- Quick retrieval from earlier learning (Add a one-digit number to a two-digit number (no new ten); Add by making a ten first). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 7 + 5: first make 10. 7 + 3 = 10. How many are left from the 5? → 2Prompt: You used 3 of the 5 to make 10.
- Use the fact 2 + 4 = 6 to work out 42 + 4. → 46Prompt: 42 is 40 + 2.
- 8 + 4: first make 10. 8 + 2 = 10. How many are left from the 4? → 2Prompt: You used 2 of the 4 to make 10.
Hook · 3 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Add a one-digit number to a two-digit number (making a new ten). 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: Sofia says 57 + 7 = 54. What is the right answer?
- Step 1: 7 + 7 = 14
- Step 2: 50 + 14 = 64
- Answer: 64
- 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.
- Isla says 35 + 9 = 34. What is the right answer? → 44Prompt: 5 + 9 is more than 9. What happens to the extra ten?
- Priya says 25 + 6 = 21. What is the right answer? → 31Prompt: 5 + 6 is more than 9. What happens to the extra ten?
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.
- Amara says 69 + 3 = 62. What is the right answer? → 72Prompt: 9 + 3 is more than 9. What happens to the extra ten?
- Sofia says 68 + 5 = 63. What is the right answer? → 73Prompt: 8 + 5 is more than 9. What happens to the extra 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 a one-digit number to a two-digit number (no new 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
- 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