Transcript What percentage of the shape is shaded white?

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Percentages
Understanding percentage as the
number of parts in every 100
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Chris Clements
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Learning Objective:
LO: I know that 'per cent' means
parts in every 100 .
Percentage (%)
The word ‘percentage’
originates from a Latin word
meaning by the hundred.
Can you think of any words
that begin with ‘cent’?
centipede
century
cents
What do you notice?
Look at the square. 100% of is shaded purple.
Can you see it is made up of 100 equal parts?
What percentage
of the shape is
shaded purple now?
What percentage
of the shape is
shaded white?
90% + 10% = 100%
What percentage
of the shape is
shaded white?
What percentage
of the shape is
shaded purple?
50% + 50% =
100%
What fraction is equivalent to 50%?
What percentage
of the shape is
shaded white?
What percentage
of the shape is
shaded purple?
25% + 75% =
100%
What fraction is equivalent to 25%?
What fraction is equivalent to 75%?
Now the square is made up of 10 different colours.
What percentage
of each colour is
there?
What fraction is
10% equivalent to?
10% x
10
=
100%
What percentage
of the shape is
shaded white?
What percentage
of the shape is
shaded purple?
37% + 63% =
100%
What percentage
of the shape is
shaded white?
What percentage
of the shape is
shaded purple?
61% + 39% =
100%
What percentage
of the shape is
shaded white?
What percentage
of the shape is
shaded purple?
88% + 12% =
100%
What percentage
of the shape is
shaded white?
What percentage
of the shape is
shaded red?
What percentage
of the shape is
shaded purple?
30% + 50% + 20% = 100%
What percentage
of the shape is
shaded white?
What percentage
of the shape is
shaded red?
What percentage
of the shape is
shaded purple?
35% + 35% + 30% = 100%
What percentage
of the shape is
shaded white?
What percentage
of the shape is
shaded red?
What percentage
of the shape is
shaded purple?
22% + 56% + 22% = 100%
What percentage
of the shape is
shaded white?
What percentage
of the shape is
shaded red?
What percentage
of the shape is
shaded purple?
50% + 46% + 4% = 100%
What do you notice
about this shape?
To work out the
percentage we
first need to find
what % each part
is worth?
To do this we need
to divide a 100 by
the number of
parts.
100% ÷ 20 = 5%
Each part = 5%
What percentage
of the shape is
shaded purple?
5% x 13 = 65%
What percentage
of the shape is
shaded white?
5% x 7 = 35%
65% + 35% = 100%
Steps to success
1) Remember one whole is equal to 100%
2) Find the percentage of parts shaded
3) Check to see if the unshaded part +
the shaded part = 100
For shapes not divided into 100 parts. Use this formula
to work out what percentage each part is worth;
100 ÷ No. of parts in a shape = % of each part
100 ÷ 2 (no. of parts) = 50%
Each part of this shape = 50%
So 50% is shaded blue
50% is shaded white
Plenary
½
25%
¼
50%
10%
75%
1
10
¾
Can you match the percentages to the
same value fraction?
34%
46%
58%
91%
19%
23%
Which of these
fractions show
more than ½?