Measuring Area

Overview

Today students measure the area of simple shapes using informal units (for example, square tiles, paper strips, or counting counters) and compare areas using the same unit.

Learning intentions

• Students will understand that area measures how much surface a shape covers.
• Students will choose and use an informal unit to measure area accurately.
• Students will count units to find the area and explain how they know it.
• Students will compare measured areas and justify statements using the same unit.

Success criteria

• I can use a single informal unit to cover a surface and avoid gaps or overlaps.
• I can count the number of units to record an area measurement.
• I can compare two shapes’ areas and explain which is larger and why.
• I can check my measurement by recounting or using a different sectioning strategy.

Curriculum links

• Measures and records area using square units and informal units suitable for Year 4.
• Interprets area as covering and uses counting to determine total area.
• Communicates measurement reasoning using mathematical language (area, unit, cover, count, equal, larger, smaller).

Lesson structure (25 minutes)

1. 1 min – Welcome & goal Tell students: “We’re going to measure area today using an informal unit and count how many fit.”

2. 4 min – Model: area is covering Display a rectangle on the board or on a table. Place square tiles (or counters on a pre-drawn grid) on it.

• Count aloud as you place tiles.
• Emphasise: “We must use the same unit each time, and tiles should not leave gaps or overlap.”

3. 6 min – Guided practice: build and count In pairs, students measure a small rectangle using a set of square tiles/counters.

• Students record the total number of units (e.g., 12 square tiles).
• Teacher circulates, prompting: “How many tiles are there? Are any tiles overlapping or missing?”

4. 6 min – Independent task: different shapes Students measure area on 3 worksheets/task cards:

• One rectangle
• One L-shape (or step shape) that can still be covered by units
• One comparison pair (Shape A and Shape B) Students record answers and a short explanation sentence such as: “I used square tiles. There are __ tiles, so Shape __ has the larger area.”

5. 4 min – Compare and justify As a class, choose 2–3 student examples (from the board or a few desks’ work).

• Focus questions: “Which unit did you use? Did you use the same unit for both shapes? How do you know your count is correct?”

6. 3 min – Quick check & exit Students complete one rapid question: “Which has greater area and why?” using the same informal unit shown. Collect responses and note common errors (gaps, overlaps, using different units).

Resources

• Square tiles (or flat counting blocks) and/or counters with a drawn grid backing
• Task cards or worksheet: rectangles, step/L-shaped figure, and a comparison question
• Student recording sheets with spaces for: shape, unit used, count, brief explanation
• Coloured pencils or crayons for outlining shapes (optional)
• Timer for timed work segments
• Teacher example mat (a larger rectangle and one L-shape on a board/table)
• Stopper cards or mini whiteboards for the final quick check (optional)
• Pairing prompts (numbered heads) if needed for discussion

Assessment

• Teacher observation during guided practice: accurate covering (no gaps/overlaps) and appropriate counting strategy.
• Review of recorded answers on the worksheet/task cards: correct unit counting and clear comparison reasoning.
• Final quick check: whether students can justify which shape has greater area using the same unit.

Differentiation

• Support: Provide a partially filled example showing correct covering; give fewer shapes (1 rectangle + 1 comparison) and additional teacher check-ins.
• Support: Offer a smaller set of unit tiles and encourage sectioning (count rows/columns) for L-shapes.
• Extension: Provide a mixed-size unit set (same shapes, different unit sizes) and ask students to explain why results change when units change; challenge them to measure in two different ways (e.g., row counting and total counting).
• EAL/SEN: Sentence starters for explanations (“I measured using…”, “I counted…”, “So the area is larger because…”). Use visual models and consistent unit vocabulary. Allow verbal responses if writing is difficult, then record for students.