Percentages

1
Percentages
National 4 NUM 1.2
Conversion between Fractions and Decimals
Percentages using a calculator
Percentage rise (Increase)
Percentage fall (Decrease)
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One quantity as a Percentage of another
Percentage Profit / Loss
Percentage Increase / Decrease
2
Starter Questions
National 4 NUM 1.2
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3
Percentages
National 4 NUM 1.2
Learning Intention
Success Criteria

1. To understand the term percentage.

1. To explain what the term percentage means and how
   it is connected to fractions and decimals.

1. Understand connection between percentages,
   fractions and decimals.

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4
Percentages
31 out of a 100
National 4 NUM 1.2
It is common to express fractions using a
denominator of a 100
means 31
means 7
7 out of a 100
5
Percentages
National 4 NUM 1.2
Q. Write down the following as a fraction and a
decimal.
27
15
2
6
Percentages
National 4 NUM 1.2
Convert these percentages to fraction and simply
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Percentages
National 4 NUM 1.2
Covert these fractions to percentages
8
Percentages
National 4 NUM 1.2
Sandra got 15 out of 20 in an maths exam. What
percentage is this.
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Franchesca has the best result.
Percentages
National 4 NUM 1.2
Franchesca got 45 out of 60 in her Maths exam and
Michael got 21 out of 30 in an English exam. Who
got the best result.
10
Percentages
National 4 NUM 1.2
Now try Ex 1 Page 41
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11
Starter Questions
National 4 NUM 1.2
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12
Percentages
National 4 NUM 1.2
Learning Intention
Success Criteria

1. To know how to calculate a percentage using a
   calculator.

1. To explain how to calculate a percentage of a
quantity using a calculator.

1. Show working.

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13
of means multiple
Percentages
National 4 NUM 1.2
Q. Find 17 of 450
Remember money 2 decimal places
14
of means multiple
Percentages
National 4 NUM 1.2
Q. Find 4 of 70
Remember !! money 2 decimal places
15
Percentages
National 4 NUM 1.2
Now try Ex2a Ch4 (page 42)
16
Starter Questions
National 4 NUM 1.2
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17
Percentage Increase
National 4 NUM 1.2
Learning Intention
Success Criteria

1. Understand terms increase for percentages.

1. To explain some simple increases in
percentages using shop prices.

1. Calculate simple increases in percentages.

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18
PercentageIncrease / Decrease
National 4 NUM 1.2
Example 2 The total hours of sunshine in June
was 260. The total for July was 5 higher than
June.. What is the total hours of sunshine in
July.
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July Total Hours
19
Simple Percentages
National 4 NUM 1.2
Now try Exercise 2b Ch4 (page 44)
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20
Starter Questions
National 4 NUM 1.2
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21
Percentage Fall (Decrease)
National 4 NUM 1.2
Learning Intention
Success Criteria

1. Understand terms decrease for percentages.

1. To explain some simple decreases in
percentages using shop prices.

1. Calculate simple decreases in percentages.

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22
Percentage Fall (decrease)
National 4 NUM 1.2
Example 1 In a sale the cost of a jumper is
reduced by 10. What is the sale price of the
jumper.
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Original Price 35
Sale Price
23
Percentage Fall (decrease)
National 4 NUM 1.2
Now try Exercise 2c Ch4 (page 47)
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24
Starter Questions
National 4 NUM 1.2
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8cm
6cm
25
Calculating Percentages
National 4 NUM 1.2
Learning Intention
Success Criteria

• To understand how to express
• A as a percentage of B.

• To understand how to express
• A as a percentage of B.

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1. Solve problems in context.

26
Calculating Percentages
National 4 NUM 1.2
Linda scored 45 out of 100 in a Maths
test. Write her score as a fraction in it
simplest form ?
Fraction
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45
What was her percentage score ?
27
Calculating Percentages
National 4 NUM 1.2
My council tax has gone up by 60. It was 300
before the increase. Calculate the council tax
increase as a percentage ?
Increase 60
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Increase
28
Calculating Percentages
National 4 NUM 1.2
My car has decreased in value to 3000. Before
the decrease it was valued at 5000. Calculate
the decrease as a percentage ?
Increase 5000 3000 2000
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decrease
29
Calculating Percentages
National 4 NUM 1.2
Now try Extension booklet Ex 3E Ch4 (page 13)
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Starter Questions
National 4 NUM 1.2
Q1. 0.5 5 x 8
Q2.
Q3.
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31
Profit and Loss
National 4 NUM 1.2
Learning Intention
Success Criteria

1. To know the meaning of the terms PROFIT and LOSS
   in terms of percentages..

• To understand the
• terms profit and loss in terms of percentages.

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1. Apply knowledge to calculations.

32
Profit and Loss
National 4 NUM 1.2
Profit When you sell something for MORE
than you bought it.
PROFIT Selling Price Buying Price
Loss When you sell something for LESS than
you bought it.
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LOSS Buying Price Selling Price
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Profit and Loss
National 4 NUM 1.2
If I buy a iPod for 200 and sell it for
220. What is my percentage profit.
220 - 200 20
I have made a PROFIT of
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increase
34
Profit and Loss
National 4 NUM 1.2
I bought a bunch of flowers for 6.00 and tried
to sell them for a profit. But I found it
difficult to sell them. I sold them for 4.00
before they went off.
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I made a LOSS of
6.00 - 4.00 2.00
decrease
35
Profit and Loss
National 4 NUM 1.2
Now try Extension booklet Ex 4E Ch4(page 16)
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36
Starter Questions
National 4 NUM 1.2
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10cm
8cm
37
Calculating Percentages
Percentage Increase / Decrease
National 4 NUM 1.2
Learning Intention
Success Criteria

1. To understand how to calculate percentage
   increase / decrease.

1. To understand how to calculate percentage
   increase / decrease.

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1. Solve problems in context.

38
Calculating Percentages
National 4 NUM 1.2
Example 1 Frances scored 13 out of 20 in a
Maths test. What was her percentage score?
A
mark
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B
39
Calculating Percentages
Percentage Increase / Decrease
National 4 NUM 1.2
Example 1 Daniel was paid 20 per week. He got
a wage rise to 22 per week. What was his
percentage increase in pay ?
A
Actual Increase 22 - 20 2
increase
B
40
Calculating Percentages
Percentage Increase / Decrease
National 4 NUM 1.2
Example 2 A house in Barlanark bought for 40
000 in 2001 was sold last week for 50 000.
Calculate the percentage increase in value?
A
Actual Increase 50 000 - 40 000 10 000
increase
B
41
Calculating Percentages
Percentage Increase / Decrease
National 4 NUM 1.2
Now try Extension Booklet Ex 5E (page 17)
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