Math lesson plan · 1st grade (Year 2 in England) · 30 minutes
Subtract by going back through ten
Addition and subtraction
CCSS 1.OA.C.6England: Y1 Addition and subtractionEngland: Y2 Addition and subtraction
Objective and success criteria
Students will: Subtract by going back through 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: Subtract within 20; Make 10 (number bonds)
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 (Subtract within 20; Make 10 (number bonds)). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- There were 16 marbles. Then 9 were used. How many are left? → 7Prompt: Are we taking away or finding a difference? Both are subtraction.
- There were 14 beads. Then 4 were used. How many are left? → 10Prompt: Are we taking away or finding a difference? Both are subtraction.
- There were 13 shells. Then 2 were used. How many are left? → 11Prompt: Are we taking away or finding a difference? Both are subtraction.
Hook · 3 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Subtract by going back through 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: 11 − 8: first take away 1 to get to 10. How much more must you take away?
- Step 1: 8 = 1 + 7
- Step 2: 7
- Answer: 7
- 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.
- 15 − 6: first take away 5 to get to 10. How much more must you take away? → 1Prompt: You must take away 6 in total.
- 11 − 9: first take away 1 to get to 10. How much more must you take away? → 8Prompt: You must take away 9 in total.
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.
- 18 − 9: first take away 8 to get to 10. How much more must you take away? → 1Prompt: You must take away 9 in total.
- 13 − 6: first take away 3 to get to 10. How much more must you take away? → 3Prompt: You must take away 6 in total.
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 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