• 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.

1. A grown-up measures a table and gets 5 hand-spans. Grace's hand is bigger. Will Grace count more or fewer hand-spans? (More / Fewer / The same) → FewerPrompt: The table does not change.
2. Ethan measured a book with paper clips and got 5. Aisha measured the same book with cubes and got 7. Which unit is longer? (The paper clip / The cube) → The paper clipPrompt: The book is the same length both times.
3. A grown-up measures a table and gets 5 hand-spans. Jamal's hand is smaller. Will Jamal count more or fewer hand-spans? (More / Fewer / The same) → MorePrompt: The table does not change.

• 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.

• 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.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. Kwame measured a shelf with cubes but let them overlap. Will Kwame's number be too big or too small? (Too big / Too small / Just right) → Too bigPrompt: Overlapping cubes cover less length each.
2. What is the right way to measure a book with paper clips? (Use paper clips of different sizes / 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 end / Spread the paper clips out with gaps to use fewer) → 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.

• 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.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. What is the right way to measure a window sill with paper clips? (Line them up end to end with no gaps or overlaps, starting at one end / Spread the paper clips out with gaps to use fewer / Use paper clips of different sizes / 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.
2. 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.

Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-1.