Math lesson plan · 1st grade (Year 2 in England) · 45 minutes
Turnaround facts: order does not change a sum
Addition and subtraction
CCSS 1.OA.B.3England: Y1 Addition and subtraction
Objective and success criteria
Students will: Turnaround facts: order does not change a sum.
- 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 10
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 10). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- There are 3 shells in a box and 1 on the table. How many shells are there in all? → 4Prompt: Are we putting groups together or taking away?
- Kofi has 3 apples. A friend gives Kofi 2 more. How many apples does Kofi have now? → 5Prompt: Are we putting groups together or taking away?
- Kwame has 1 marbles. A friend gives Kwame 8 more. How many marbles does Kwame have now? → 9Prompt: Are we putting groups together or taking away?
Hook · 5 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Turnaround facts: order does not change a sum. 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: 6 + 2 = 8. So 2 + 6 = ?
- Step 1: Changing the order does not change the sum.
- Step 2: 2 + 6 = 8
- Answer: 8
- 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.
- 2 + 8 = 10. So 8 + 2 = ? → 10Prompt: The same two numbers are being added.
- Which has the same answer as 7 + 8? (7 + 7 / 8 − 7 / 8 + 8 / 8 + 7) → 8 + 7Prompt: Look for the same numbers added in a different order.
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.
- Kwame says: "9 − 2 is the same as 2 − 9, just like adding." True or false? (True / False) → FalsePrompt: Can you take 9 away from 2 and stay in the numbers you know?
- Which has the same answer as 6 + 3? (6 + 6 / 6 − 3 / 3 + 7 / 3 + 6) → 3 + 6Prompt: Look for the same numbers added in a different order.
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 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