Compare Lengths

Overview

In this first unit lesson, students compare familiar objects by length and height using direct visual comparison. They build on everyday language and begin to line objects up at the same starting point so comparisons are accurate.

Learning intentions

• Students will be able to compare objects by length and height.
• Students will be able to use the words long, short, tall, same, longer, and shorter.
• Students will be able to order three objects from shortest to longest.
• Students will be able to explain a comparison using a complete sentence.

Success criteria

• I can line objects up at the same starting point.
• I can tell which object is longer, shorter, or taller.
• I can use a comparison word to explain my thinking.
• I can put three objects in order from shortest to longest.

Curriculum links

• Measurement — selecting and using appropriate tools and strategies to measure length.
• Measurement — solving length comparison problems using addition and subtraction ideas and a symbol or statement for the unknown.
• Measurement — representing whole numbers as lengths on equally spaced number lines.
• Measurement — recognizing that measurements change when the size of the unit changes.

Lesson structure (30 minutes)

1. 0–3 min · Hook and learning intention. Teacher opens with the opening comparison image showing two objects that appear different in length and asks, “Which one is longer? How do you know?” Teacher reads the “I can” statement aloud. Students make a quiet estimate, show an A/B response, and share one idea with a partner.

2. 3–8 min · I do: model fair comparison. Teacher uses the modeling slides and two large classroom objects, such as a pencil and a book, to demonstrate placing both objects at the same starting point; model the words longer, shorter, and same. Students watch, copy the hand gesture for each word, and repeat the sentence frame: “The ___ is longer/shorter than the ___.”

3. 8–15 min · We do: compare together. Teacher displays pairs of large picture cards and real objects through the guided practice slides. For each pair, invite students to line up or point to the objects, then ask, “Which is longer?” or “Which is shorter?” Students compare in pairs, use gestures, and hold up A or B; each student gives at least one oral comparison using a vocabulary word.

4. 15–18 min · Mini-lesson 2: length and height. Teacher revisits the difference between comparing length from end to end and height from bottom to top, using a cup and a door or two picture cards; display the visual reminder in the length and height reminder. Students stand objects upright when comparing height and explain why the objects must start at the same level.

5. 18–26 min · You do: order three objects. Teacher gives each student three safe classroom objects or picture strips and models the direction once using the ordering directions. Students arrange their three objects from shortest to longest, check that the ends are lined up, and tell the teacher or a partner, “The ___ is shortest, the ___ is next, and the ___ is longest.” Students then complete the picture-supported tasks on the compare and order worksheet without a copying requirement.

6. 26–30 min · Check and close. Teacher uses the closing review slides to revisit the vocabulary and gives the five-item oral/picture assessment. Students respond by pointing, choosing A/B/C, or arranging picture strips, then complete the “I can” self-check orally or by circling an icon on the worksheet.

Resources

• Compare Lengths visual slide deck
• Compare Lengths picture-supported worksheet
• Large picture cards of familiar objects
• Pencil, book, shoe, cup, and other safe classroom objects
• Three picture strips or object cards per student
• A/B/C response cards or cards labeled longer, shorter, taller, and same
• Chart paper or whiteboard
• Large, high-contrast vocabulary cards

Assessment

• During guided practice, check whether each student lines objects up at the same starting point and uses a comparison word. Prompt with “Show me where the objects should begin.”
• Ask: “Which is longer: the pencil or book?” “Which is shorter: the shoe or table?” “Which is taller: the cup or door?” “Are these the same length?” Students answer with picture-supported A/B choices.
• Ask students to put three picture strips in order from shortest to longest. Record whether each student orders correctly and can explain one comparison.

Differentiation

• For students needing support, offer only two choices, use large high-contrast objects, provide a clear starting line, and repeat one sentence frame: “The ___ is ___ than the ___.”
• Provide hand-over-hand or guided physical support when students line up objects, then gradually reduce assistance. Allow pointing, gestures, eye gaze, or A/B/C cards instead of requiring spoken or written answers.
• For students ready for a challenge, provide three objects with close lengths and ask them to justify the complete order, identify the middle object, or find two objects that are the same length.
• For dyslexia-friendly access, read every direction and question aloud, use large sans-serif print, strong contrast, generous spacing, and icons. Avoid copying; students may circle, point, match, or respond orally. Use repeated vocabulary and model each word with a gesture.