TOPIC
Area
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Strand: Measures
Strand unit: Area
Curriculum Objectives
651
652
653
654
655
656
Recognise that the length of the perimeter of a rectangular shape does not
determine its area.
Calculate the area of regular and irregular 2D shapes.
Measure the surface area of specified 3D shapes.
Calculate area using ares and hectares.
Identify the relationship between square metres and square centimetres.
Find the area of a room from a scale plan.
Looking back: What the 5th class programme covered
1. Square centimetres and square metres.
2. Measurement of the area of regular and irregular 2D shapes.
3. Formula to calculate area of a rectangle.
Maths skills used in this topic
1. Applying and problem-solving: Apply mathematical concepts and processes, and plan and
implement solutions to problems, in a variety of contexts.
2. Implementing: Implement suitable standard and non-standard procedures with a variety of
tools and manipulatives.
3. Understanding and recalling: Understand and recall facts, definitions and formulae.
Concrete materials
Instruments to measure length
Vocabulary
Perimeter, are, hectare
Teaching points
1. The terms ‘square metres’ and ‘metres square’ are not interchangeable. The correct term
when referring to an area in m2 is square metres. The term ‘metres square’ is used in the
following context: ‘A room is 6 metres square. What is its area?’
Here we are told that the room is square in shape and that each side measures 6m. Therefore
its area is 36 square metres. Therefore, 6 metres square = 36 square metres.
2. Objective 651 (Recognise that the length of the perimeter of a rectangular shape does not
determine its area) can make for some interesting practical work. The children
should conclude that the area of a rectangle does not determine its perimeter
and that the perimeter of a rectangle does not determine its area.
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Oral and mental activities
Fans:
Show the area of squares measuring 4cm, 10cm, 12cm, 8cm, etc. Show the area of rectangles
whose sides measure 6cm by 10cm, 4cm by 8cm, 2m by 5m, etc. Ensure that the children say
square centimetres or square metres when answering. The area of a square is 36cm2, 49cm2, etc.
What is the length of its sides?
Loop game (see Folens Online resources):
Area
Topic suggestions
1. The authors can’t emphasise enough the importance of estimation. Key to that is exposure to
examples of a square metre, are and hectare – examples that will live in the children’s minds.
This has a further beneficial effect in the realm of problem solving. Lots of wrong answers
to problems can be easily identified by the child who knows that an answer can’t possibly
be correct: the child who calculates the area of a room to be 1.4m2 or that the school yard
measures 0.25 of an are.
2. Carry out practical work on the topic – area of classroom, corridor, yard, hall. Perhaps make a
square metre from newspaper, use a trundle wheel for long distances, compare areas that are
long and narrow with areas that are almost square. How many maths books would I need to
cover 1m2? How many cars might fit in a car park that measures 1 are?
Activity A
Model 2 is more difficult than model 1 because it does not have a cm2 grid superimposed.
Model 1:
1. What is the area of the red, blue, green, etc. rectangle? (red,12cm2; green, 10cm2; blue,
18 cm2; yellow, 6cm2; pink, 6cm2; white 8cm2; orange 4cm2)
2. What is the area of the large square (total area)? (64cm2)
3. What is the perimeter of the red, blue, green, etc. rectangle? (red,16cm; green, 14cm;
blue, 18 cm; yellow, 10cm; pink, 6cm; white 14cm; orange 8cm)
4. What is the area of the red and blue, yellow and white, and green and yellow rectangles?
(30cm2, 12cm2, 16cm2)
5. What is the perimeter of the green and blue area, pink and blue space? (32cm, 24cm)
6. What is the area of all of the shape except for the blue area? (46cm2)
7. What is the perimeter of all of the shape except for the blue, etc. part?
Model 2:
1. What are the areas of the large yellow square and the small yellow square? (25cm2, 9cm2)
2. What is the area of the large yellow square, excluding the small yellow square? (16cm2)
3. What is the area of the large square (total area)? (64cm2)
4. What is the area of the large square, excluding the small yellow square? (55cm2)
5. What are the areas of the large green rectangle and the small green rectangle? (24cm2,
6cm2)
6. What is the area of the large green rectangle, excluding the small green rectangle? (18cm2)
7. What are the areas of the red rectangle and the dark red triangle? (6cm2, 3cm2)
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8. What are the areas of the blue rectangle and the dark blue triangle? (9cm2, 5cm2)
9. What are the perimeters of the large green rectangle and the small green rectangle?
(22cm, 14cm)
10. What is the perimeter of the L-shape formed by combining the large green rectangle with
the large blue rectangle? (28cm)
Differentiation
Lower attainers:
Separate activity sheet
Higher attainers:
1. Separate activity sheet
2. What type of rectangle yields the largest area for the smallest perimeter? This might be
given to the children as a problem as follows: Tom buys 20m of fence. What is the largest
rectangular area he can enclose? He could make a 9 x 1, 8 x 2, 7 x 3, 6 x 4 or a 5 x 5
rectangle, assuming we stick to whole numbers. Try other numbers (use multiples of 4 so that
it is always possible to create a square).
Topic
Topic
18
18
1. Draw rectangles with the following areas. Find the perimeter of each rectangle you have drawn.
(a) 8cm2
(b) 10 cm2
(c) 12 cm2
(d) 15 cm2
(e) 16 cm2
1. In your head. Calculate the area of these rectangles.
(a) L 15m W 6m: ________
(f) 21 cm2
(b) L 20m W 12m: ________
(c) L 15m W 10m: ________
(d) L 11m W 3m: ________
(e) L 12m W 8m: ________
(f) L 40m W 20m: ________
(g) L 5m W 12 m: ________
(h) L 6m W 14 m:
________
(i) L 0.5m W 0.4m: ________
2. Find the area of these rectangles. You are given the perimeter and the length.
(a) P 10m L 4m: ________
(b) P 14m L 5m: ________
(c) P 20m L 7m: ________
(d) P 28m L 10m: ________
(e) P 30m L 10m: ________
(f) P 40m L 15m: ________
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(h) P 6m L 2 12 m: ________
(i) P 9m L 3m:
(g) P 4m L 1 2 m: ________
________
3. Answer the questions.
(a) A square garden is 20m long. There is a square flower bed which is 6m long in the centre of
the garden. What is the area of the garden around the flower bed? ________
2. Draw rectangles with the following perimeters. Find the area of each rectangle you have drawn.
(a) 4cm
(b) 8cm
(c) 10cm
(d) 18cm
(e) 20cm
(b) A cube has edges measuring 8m. What is the surface area of the cube? ________
(f) 26cm
(c) A cuboid has edges measuring 6m by 5m by 3m. What is the surface area? ________
whiteboard
(a) What is the area of the classroom? ________
1
2m
(b) What is the area of the ‘wet area’? ________
1 12 m
1m
9m
4. Look at the plan of a classroom.
8m
5. (a) What is the surface area of one desk? ________
(b) What is the surface area of all of the desks? _______
6. All of the classroom has carpet except for the wet area.
2m
What is the area of the carpet? ________
Wet Area
4m
7. A classroom projector is built into the ceiling. It is situated 2 12 m from the whiteboard. Estimate its
position and place an X on the plan to represent the projector.
3. Find the area and perimeter of each of these rectangles.
(c) L 11cm, W 3cm: ___
(e) L 20cm, W 16cm: ___
(f) L 32cm, W 25cm: ___
(a) L 7cm: ___
(b) L 9cm: ___
(d) L 15cm: ___
(e) L 22cm: ___
Name: _______________________________________
(c) L 11cm: ___
(f) L 44cm: ___
Date: ___________________
Page 157: Area
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8. What is the perimeter of the room, including the door? ________
9. What is the perimeter of the carpeted part of the room, including the door? ________
10. Six classrooms like this one are in a line. A 2m wide corridor runs alongside the classrooms,
adjacent to the door. What is the area of the corridor? ________
Name: _______________________________________
Date: ___________________
© Folens Photocopiables
(b) L 8cm, W 7cm: ___
© Folens Photocopiables
(a) L 10cm, W 5cm: ___
(d) L 12cm, W 10cm: ___
4. Find the area and perimeter of each of these squares.
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Page 158: Area
Linkage
Measures: Length (perimeter)
Integration
SESE Geography: Area of counties, countries
Maths at home/parental involvement
1.
2.
3.
4.
5.
Which rooms in your home have the greatest and smallest areas?
Think of things in your locality with an approximate area of 1 are and 1 hectare.
Which window in your house has the greatest surface area?
Do all the doors in your home have the same surface area?
The covers of which books in your home have the greatest and smallest surface area?
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