The aim of the session is to reinforce methods of teaching the
following topics across the curriculum.
Find perimeters of shapes with straight sides. 7.M2
Read and interpret scales on a range of measuring instruments. 7.M1
Convert between units of the metric system and carry out calculations.
7.M3
Use the common units of measure, convert between related units.
8.M3
Use rough metric equivalents of imperial units in daily use. 8.M3a
Use formulae for the area of rectangles and triangles. 7.M10
Calculate areas of compound shapes (e.g. consisting of rectangles).
8.M10
Find circumferences of circles. 9.M2
The perimeter of a shape is the total length of its boundary.
Example
Find the perimeter of the shape.
First we need to work out the
length of any missing sides.
Perimeter = 4 + 7 + 6 + 2 + 10 + 9
= 38 cm
What measurement is shown on Jug A and Jug B.
Jug A
Large division is 500 ml
Each large division is sub
divided into 5 smaller divisions.
1 small division = 500
5
1 small division = 100 ml
4 x 100 = 400 ml
Jug B
Large division is 100 ml
Each large division is sub divided
into 5 smaller divisions.
1 small division = 100
5
1 small division = 20 ml
300 + (1 x 20)
300 + 20
320 ml
Metric Units
Length
10 mm = 1 cm
100 cm = 1m
1000 m = 1 km
Mass
1000g = 1Kg
1000kg = 1 tonne
Volume
1000ml = 1000 cm3 = 1 litre
Example
The length of a classroom is 887 cm. How long is that in
metres?
We would expect the answer in m to be smaller as we are
changing to a bigger unit of measurement. To make a
number smaller we would divide.
887 = 8.87 m
100
Emma is having a party with some friends. She has
2.5 litres of orange juice. How many 250 ml cups can be
filled from it?
First we need to convert to work in the same units
(ml).We would expect the answer in ml to be bigger as
we are changing to a smaller unit of measurement. To
make a number bigger we would multiply.
2.5 x 1000 = 2500 ml
2500 = 10 cups
250
5 miles ≈ 8 km
2.2 lb ≈ 1 kg
1.75 pints ≈ 1 litre
To convert from miles into km divide by 5 then multiply by 8
To convert from km into miles divide by 8 then multiply by 5
To convert from lb into kg divide by 2.2
To convert from kg into lb multiply by 2.2
To convert from pints into litres divide by 1.75
To convert from litres into pints multiply by 1.75
Examples
How many kilometres is 120 miles?
To convert miles into kilometres divide by 5 then
multiply by 8.
120 = 24
5
24 x 8 = 192 km
Convert 33 lb into kilograms
To convert from lb into kg divide by 2.2
33
2.2
= 15 kg
How many pints are there in 14 litres
To convert from litres into pints multiply by 1.75
14 x 1.75 = 24.5 pints
Rectangle
Area = length x width
width
length
Example
Calculate the area of the rectangle
5 cm
8 cm
A =lxw
A= 8x5
A = 40 cm2
Units of measurement for area are units2
Triangle
Area = base x height
2
height
height
base
base
Example
Calculate the area of the triangle.
12 cm
5 cm
A=bxh
2
A = 5 x 12
2
A = 60
2
A = 30 cm2
A compound shape is made by joining basic shapes together.
To find the area of a compound shape first split the shape into
its component parts, find the area of each part then add the
areas together.
Example
Area A = l x w
= 10 x 2
= 20 cm 2
Total Area = 20 + 28
= 48 cm2
Area B = 1 x w
=7x4
= 28 cm2
Circumference of a circle
C = 2Лr
C=2xЛxr
where r = radius
Examples
Find the circumference of a circle whose radius is 6 cm.
C = 2Лr
C=2xЛx6
C = 37.7 cm
A circular disc has a diameter of 5 cm. Find the
perimeter of the disc.
Radius = diameter
2
Radius = 5
2
= 2.5 cm
The circumference is the perimeter of a circle.
C = 2Лr
C = 2 x Л x 2.5
C = 15.7 cm