Math lesson plan · 1st grade (Year 2 in England) · 45 minutes
Subtract by counting back
Addition and subtraction
CCSS 1.OA.C.5CCSS 1.OA.C.6England: Y1 Addition and subtraction
Objective and success criteria
Students will: Subtract by counting back.
- 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 10; Count back from 10 and from 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 (Subtract within 10; Count back from 10 and from 20). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Count back: 10, 9, 8, __ → 7Prompt: Counting back, each number is one less.
- Noah has 9 stars. Ravi has 1. How many more stars does Noah have than Ravi? → 8Prompt: Is something being taken away, or are we comparing?
- Nia has 8 cookies. Ines has 1. How many more cookies does Nia have than Ines? → 7Prompt: Is something being taken away, or are we comparing?
Hook · 5 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Subtract by counting back. 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: 12 − 1 = ?
- Step 1: 11
- Step 2: 12 − 1 = 11
- Answer: 11
- 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.
- 20 − 2 = ? → 18Prompt: Start at 20.
- Sofia worked out 16 − 3 by saying "16, 15, 14" and answered 14. What is the right answer? → 13Prompt: Sofia counted the starting number 16 as one of the steps.
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.
- 15 − 2 = ? → 13Prompt: Start at 15.
- Priya worked out 11 − 3 by saying "11, 10, 9" and answered 9. What is the right answer? → 8Prompt: Priya counted the starting number 11 as one of the steps.
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 10.
- 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