Slide tiles into the rectangle one at a time on the IWB grid as pupils settle. Ask the gap-or-overlap question and take two or three hands-up answers; don't reveal the word area yet.

Draw a quick finger along the outside edge to mean around (the space along the edge pupils have measured before) and a flat hand across the middle to mean inside (area, today). Revoice a strong answer: so this time we are counting the space the shape covers, not the edge.

Walk each example aloud, one at a time. Point at each square as the class counts in unison up to the total.

• 3 by 4 rectangle — emphasise that every square is the same size; say the answer twelve square centimetres and write 12 cm² on the board.
• L-shape — head off the idea that area only works on rectangles; the count still works for any shape with no gaps.
• Triangle — this is the key new idea. The sloped edge cuts squares in half. Point to two matching half-squares along the slope and say two halves make one whole. Do not rush this.

Keep stressing the unit name aloud: every answer ends in square centimetres, written cm².

This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud.

The outline is a single 5 by 3 patch. Call one pupil up to count the square units aloud while the class follows, then call a second and a third to count the same patch again, so several pupils get a turn on one shape. Have each one write area = ___ cm² so the unit is always attached.

Watch for the two common slips: skipping a square in the middle of a block, and counting a boundary square twice. Revoice a careful counter: see how she touched every square once — that is how we keep the count fair.

This round is the practice bank — pupils take turns at the board (and at their squared paper) to cover each outline and count it, and the class confirms the total before moving on. Keep the board work brisk rather than over-explaining.

The three outlines should be pre-drawn on the squared paper handed out before the lesson, so pupils have something to cover and count rather than measuring from scratch. The triangle outline is where to slow down: point to the two matching half-squares along the slope and confirm aloud that they join to make one whole square. For the stretch, the strong insight is that two shapes can look completely different yet share the same area — name it when a pupil produces it.

Recap the four bullets briskly, drawing one last attention to the cm² unit. Preview the rows-by-columns shortcut without teaching it — that is the next lesson.