Math lesson plan · 1st grade (Year 2 in England) · 45 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 · 5 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 + 9: first make 10. 7 + 3 = 10. How many are left from the 9? → 6Prompt: You used 3 of the 9 to make 10.
- Use the fact 2 + 7 = 9 to work out 92 + 7. → 99Prompt: 92 is 90 + 2.
- 8 + 7: first make 10. 8 + 2 = 10. How many are left from the 7? → 5Prompt: You used 2 of the 7 to make 10.
Hook · 5 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 · 10 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 · 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 says 65 + 7 = 62. What is the right answer? → 72Prompt: 5 + 7 is more than 9. What happens to the extra ten?
- Sam says 28 + 7 = 25. What is the right answer? → 35Prompt: 8 + 7 is more than 9. What happens to the extra ten?
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.
- Maya says 78 + 9 = 77. What is the right answer? → 87Prompt: 8 + 9 is more than 9. What happens to the extra ten?
- Diego says 36 + 8 = 34. What is the right answer? → 44Prompt: 6 + 8 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