Math lesson plan · 1st grade (Year 2 in England) · 60 minutes
Spot measuring mistakes: gaps and overlaps
Measurement
CCSS 1.MD.A.2England: Y1 Measurement
Objective and success criteria
Students will: Spot measuring mistakes: gaps and overlaps.
- 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: Measure with same-size units and compare unit sizes
Leads to: the next skill in this area.
Materials: Rulers, scales and measuring jugs, Clock faces, Conversion chart, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 6 min
- Quick retrieval from earlier learning (Measure with same-size units and compare unit sizes). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- A grown-up measures a table and gets 11 hand-spans. Zara's hand is smaller. Will Zara count more or fewer hand-spans? (More / Fewer / The same) → MorePrompt: The table does not change.
- Ines measured a book with paper clips and got 7. Liam measured the same book with cubes and got 12. Which unit is longer? (The paper clip / The cube) → The paper clipPrompt: The book is the same length both times.
- A grown-up measures a table and gets 11 hand-spans. Kai's hand is bigger. Will Kai count more or fewer hand-spans? (More / Fewer / The same) → FewerPrompt: The table does not change.
Hook · 6 min
- Ask the class to estimate the length of the room or the weight of a bag before measuring it.
- Share the objective: Spot measuring mistakes: gaps and overlaps. Read the success criteria together.
I do: model it · 12 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Kofi measured a shelf with cubes but left gaps between them. Will Kofi's number be too big or too small?
- Step 1: Gaps mean fewer cubes are counted: too small.
- Step 2: Too small
- Answer: Too small
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 12 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Tariq measured a shelf with cubes but left gaps between them. Will Tariq's number be too big or too small? (Too big / Too small / Just right) → Too smallPrompt: The gaps cover some of the shelf without a cube.
- What is the right way to measure a book with paper clips? (Spread the paper clips out with gaps to use fewer / Use paper clips of different sizes / Line them up end to end with no gaps or overlaps, starting at one end / Pile the paper clips on top of each other in the middle) → Line them up end to end with no gaps or overlaps, starting at one endPrompt: Every bit of the length must be covered exactly once.
You do: independent practice · 17 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 · 7 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Yuki measured a shelf with cubes but let them overlap. Will Yuki's number be too big or too small? (Too big / Too small / Just right) → Too bigPrompt: Overlapping cubes cover less length each.
- What is the right way to measure a desk with straws? (Use straws of different sizes / Pile the straws on top of each other in the middle / Spread the straws out with gaps to use fewer / Line them up end to end with no gaps or overlaps, starting at one end) → Line them up end to end with no gaps or overlaps, starting at one endPrompt: Every bit of the length must be covered exactly once.
Watch out for
- Measuring from the end of the ruler instead of zero.
- Converting units the wrong way (multiplying instead of dividing).
Support and stretch
Support
- Review first: Measure with same-size units and compare unit sizes.
- Use concrete materials: rulers, scales and measuring jugs.
- 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