Notes for whole chapter
- Remind students to put units with all of their answers.
- Remind students to check that all the units in the problems are the same.
- Encourage students to estimate their answers first.
- Encourage students to write down their working.
1. Hetty’s quilt (perimeter task)
- Encourage students to find a systematic way of approaching this problem.
2. Would you like this gift-wrapped? (area and perimeter task)
- This is best given to a pair or group of students.
- You could get the students to model this task using paper and blocks.
3. Designer containers (area and volume task)
- Students should be reminded that the surface area of a shape is the sum of the areas of all the faces.
- Students should be encouraged to think about what each container could hold to help them choose appropriate dimensions for
the nets.
4. How much will it hold? (volume task)
- Encourage students to find a systematic way of approaching this problem.
Notes for whole chapter
- Remind students to put units with all of their answers.
- Remind students to check that all the units in the problems are the same.
- Encourage students to estimate their answers first.
- Encourage students to write down their working.
Teaching ideas
Ask students to write down all the units of area that they know and discuss how square centimetres and cm2 mean the same thing. Discuss what the 2 means in cm2.
This link displays some rectangles for part 1a and some triangles for part 2a that you could use as a class practical, rather than students drawing their own.
This link displays pictures of the Eiffel Tower and other structures that have been made using triangles.
Students are asked why they think triangles were used.
Teacher notes
- Students need to know the units of area and that square centimetre is the same as cm2 and why. Link this to squaring numbers.
2 x 2 = 22 so cm x cm = cm2. - Remind students that a hectare is 100 m by 100 m or 10 000 m2.
- It is important that students understand where the formula for the area of a triangle comes from.
Notes for whole chapter
- Remind students to put units with all of their answers.
- Remind students to check that all the units in the problems are the same.
- Encourage students to estimate their answers first.
- Encourage students to write down their working.
Teaching ideas
This link displays the Getting started on page 210 for you to use.
This link displays shapes for you to print and cut out.
Join any of these shapes together and then draw around them to show students that when looking at a shape they need to see if it can be split into shapes that they recognize and can use to find the area.
Example:
Display other shapes for students to work out how they could break them up into rectangles, triangles and parallelograms to enable them to find the area. Sometimes this can be done in more than one way.
This link displays some shapes where students have to find the lengths of the missing sides.
Teacher notes
- Encourage students to copy the diagrams into their books and clearly identify how the shape can be split up into rectangles, parallelograms and triangles.
- Encourage students to write on to their diagrams all the lengths that can be worked out using the ones they have.
Notes for whole chapter
- Remind students to put units with all of their answers.
- Remind students to check that all the units in the problems are the same.
- Encourage students to estimate their answers first.
- Encourage students to write down their working.
Teaching ideas
This link displays the instructions for a practical activity that requires students to work out the volume of a cuboid of playdough and then how thick it would be if it was spread into a rectangular shape of side 25 cm by 30 cm.
They then spread the playdough and check.
Teacher notes
- Encourage students to do as many of these problems mentally and using written methods as possible but check their answers using a calculator.
- Some of the problems are quite challenging and students might be best paired or working in groups.
Area of triangles (Teaching resource sheet 61)