Math lesson plan · 1st grade (Year 2 in England) · 30 minutes
Spot the place-value mistake
Number sense
CCSS 1.NBT.B.2England: Y1 Number and place valueEngland: Y2 Number and place value
Objective and success criteria
Students will: Spot the place-value mistake.
- 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: Split two-digit numbers into tens and ones
Leads to: the next skill in this area.
Materials: Place value chart, Base-ten blocks or a number line, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 4 min
- Quick retrieval from earlier learning (Split two-digit numbers into tens and ones). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- 47 = __ + 7 → 40Prompt: How many tens and how many ones are in 47?
- 9 + 50 = ? → 59Prompt: One number is the tens and the other is the ones.
- Which shows 57 split into tens and ones? (50 + 7 / 5 + 7 / 50 + 70 / 70 + 5) → 50 + 7Prompt: 57 has 5 tens. What are 5 tens worth?
Hook · 3 min
- Show a number in the news or a price tag and ask what each digit is worth.
- Share the objective: Spot the place-value mistake. 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: Amara says 2 tens and 4 ones make 24. Is Amara right?
- Step 1: 20 + 4 = 24
- Step 2: Yes, that is right.
- Answer: Yes
- 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.
- Leo says 2 tens and 3 ones make 23. Is Leo right? (Yes / No) → YesPrompt: The tens digit is written first.
- Liam wrote "twenty-nine" as 209. What should Liam have written? → 29Prompt: Liam wrote the 20 and then the 9 next to it.
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.
- Sam wrote "twenty-nine" as 209. What should Sam have written? → 29Prompt: Sam wrote the 20 and then the 9 next to it.
- Tariq says 2 tens and 4 ones make 42. Is Tariq right? (Yes / No) → NoPrompt: The tens digit is written first.
Watch out for
- Reading 1,045 as one thousand four hundred five: point to each place and say its value.
- Thinking a longer number is always bigger, even with decimals (0.45 vs 0.5).
Support and stretch
Support
- Review first: Split two-digit numbers into tens and ones.
- Use concrete materials: place value chart.
- 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