• Quick retrieval from earlier learning (Area of composite rectilinear shapes; Perimeter of L-shapes and other rectilinear shapes). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. An L-shape is made by cutting a 5 yd by 3 yd rectangle from the corner of a 7 yd by 10 yd rectangle. What is the area of the L-shape, in yd²? → 55Prompt: Find the area of the big rectangle.
2. An L-shape is made by cutting a small rectangle, 6 cm by 7 cm, from one corner of a big rectangle, 10 cm by 9 cm. What is the perimeter of the L-shape? → 38Prompt: Find all six side lengths of the L-shape.
3. A garden is made of two rectangles: 8 ft × 6 ft and 8 ft × 3 ft. What is the total area, in ft²? → 72Prompt: Find the area of each rectangle.

• Show a photo of a building, a tile pattern or a road sign and ask what shapes and angles students can spot.
• Share the objective: Area of compound shapes with missing lengths. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: An L-shape is made from a big rectangle, 14 m by 5 m, with a small rectangle, 4 m by 3 m, cut from one corner. What is its area?
• Step 1: 14 × 5 = 70
• Step 2: 4 × 3 = 12
• Step 3: 70 − 12 = 58 m²
• Answer: 58
• 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. An L-shape is made from a big rectangle, 7 m by 9 m, with a small rectangle, 3 m by 2 m, cut from one corner. What is its area? → 57Prompt: Find the area of the big rectangle.
2. An L-shaped room: the bottom wall is 13 m, the left wall is 9 m, the top wall is 8 m and the right wall is 5 m. The other two walls are not labelled. What is the floor area? → 97Prompt: The missing lengths are 13 − 8 and 9 − 5.

• 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.

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

1. An L-shaped room: the bottom wall is 14 m, the left wall is 9 m, the top wall is 9 m and the right wall is 7 m. The other two walls are not labelled. What is the floor area? → 116Prompt: The missing lengths are 14 − 9 and 9 − 7.
2. An L-shape is made from a big rectangle, 10 m by 12 m, with a small rectangle, 4 m by 5 m, cut from one corner. What is its area? → 100Prompt: Find the area of the big rectangle.

Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-5.