TOPIC
23
Area
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Strand: Measures
Strand unit: Area
Estimate, compare and measure the area of regular and irregular shapes.
Looking back: What the 3rd class programme covered
1. Estimating, comparing and measuring area of regular and irregular shapes in
non-standard squares.
Maths skills used in this topic
1. Implementing: Execute standard procedures efficiently with a variety of tools.
2. Integrating and connecting: Make mathematical connections within mathematics itself,
throughout other subjects and in applications of mathematics in practical everyday contexts.
Squared centimetre paper, rulers and metre sticks
Vocabulary
Length, width, breadth
Teaching points
1. Many pupils will realise that in finding the area of a rectangle, there is a shortcut: multiply the
number of rows by the number of squares in each, multiply the number of columns by the
number of squares in each or multiply the length by the width.
2. Finding the area of irregular shapes is more difficult. We superimpose a grid of square
centimetres on the shape and count. The children will need to decide if a given square is more
than half filled (in which case it’s counted) or less than half filled (in which case it isn’t). Discuss
accuracy – is this method completely accurate?
Fans:
What is the area of a square whose sides are:
(a) 5cm? (b) 6cm? (c)10cm?
What is the area of a rectangle whose side are:
(a) 4cm and 3 cm?
(b) 6cm and 7 cm?
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Topic suggestions
Units of area are correctly named square centimetres and square metres. Have the children form
the habit of saying these correctly. They are not centimetres square(d) or metres square(d). If a
room is described as 5 metres square, it is in the shape of a square and has an area of 25 square
metres.
Activity A
1. (Left-hand side) Defining length and width of the rectangles:
(a) Which rectangle has the greatest length?
(b) Which rectangle has the shortest width?
2. (Left-hand side) Turn your maths book sideways and look at the rectangles:
(a) Is the length still the length?
(b) Which shape has equal length and width?
3. (Left-hand side) How many squares make up each rectangle? (At this point some children
may realise the connection between multiplication (l x w) and area).
4. Are the squares in the diagram on the left the same size as the squares in the diagram on
the right? Discuss importance of standardisation.
5. (Right-hand side) How many squares make up each shape?
Differentiation
Lower attainers:
Refer to photocopiable.
Higher attainers:
Children who realise that l x w = may be given less concrete tasks. Find the area of a rectangle
whose length is 12cm and width is 8cm, etc. Further to this, some children may be able to work
out the width when given the length and area.
Topic
23
1. What is the area of each shaded rectangle?
(e)
(a)
(f)
(d)
(c)
(b)
(g)
(a) ____
(b) ____
(c) ____
(d) ____
(e) ____
(f) ____
(g) ____
2. What is the area of each shape?
(f)
(d)
(c)
(a)
(e)
(b)
(b) ______
(c) ______
(d) ______
(e) ______
Date: ___________________
(f) ______
© Folens Photocopiables
(a) ______
Name: _______________________________________
Linkage
Number: Operations (multiplication (l x w));
Shape and Space: 2D shapes
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Integration
SESE Geography: Areas of countries, counties, playing fields, etc.
Maths at home/parental involvement
Carry out an area trail at home
Which room in your house has the greatest area? Which room has the smallest area? Is the area
of the upstairs floor of a 2-storey house exactly the same as the area of the downstairs floor?
What might cause these areas to be different? (downstairs extension, porch) Could the area
of upstairs ever be greater than the area of downstairs? (unlikely, but not impossible) Which
table at home has the greatest surface area? Which would have the greater area – a flat roof or
a pitched roof? (Which would need more tiles?) Would you need to know the area of a floor
if you were buying carpet, lino, wood? How do builders create lots of living space if they only
have a small area to work in? (build tall apartments and skyscrapers – think of high density
housing in many cities)
Notes
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