Percentage increase/decrease

Good morning!
Schedule: 
  • Learning goals 
  • Percentage increase
  • Percentage decrease
  • Practice
  • Homework
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MaatschappijleerMiddelbare schoolvwoLeerjaar 2

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Good morning!
Schedule: 
  • Learning goals 
  • Percentage increase
  • Percentage decrease
  • Practice
  • Homework

Slide 1 - Diapositive

Good morning!
Schedule: 
  • Learning goals 
  • Percentage increase
  • Percentage decrease
  • Practice
  • Homework

Slide 2 - Diapositive

Learning goals 
At the end of this lessons I can:
  • Calculate percentage increases and decreases
  • Calculate the price of something after a discount 
  • Calculate a quantity after a percentage increase or decrease

Slide 3 - Diapositive

Percentage increase/decrease

Slide 4 - Diapositive

Where do you see percentage increase or decrease in your real-life?
Give 1 example

Slide 5 - Question ouverte

Percentage increase
1. Calculate the percentage of the original value
2. Add this percentage to the original value

Slide 6 - Diapositive

Percentage increase
1. Calculate the percentage of the original value
2. Add this percentage to the original value
(3. Write your conclusion)

Ex. Dylan worked 35 hours in November. He has worked 30% more in December. How much did he work in December? 

Slide 7 - Diapositive

Dylan worked 35 hours in November. He has worked 30% more in December. How much did he work in December?

Slide 8 - Question ouverte

Percentage increase
1. Calculate the percentage of the original value
2. Add this percentage to the original value
(3. Write your conclusion)
Ex. Dylan worked 35 hours in November. He has worked 30% more in December. How much did he work in December? 
1. 30% of 35             10% of 35 is 3.5             30% of 35 is 10.5

Slide 9 - Diapositive

Percentage increase
1. Calculate the percentage of the original value
2. Add this percentage to the original value
(3. Write your conclusion)
Ex. Dylan worked 35 hours in November. He has worked 30% more in December. How much did he work in December? 
1. 30% of 35             10% of 35 is 3.5             30% of 35 is 10.5
2. 35 + 10.5 = 45.5 hours

Slide 10 - Diapositive

Percentage increase
1. Calculate the percentage of the original value
2. Add this percentage to the original value
(3. Write your conclusion)

1. 30% of 35             10% of 35 is 3.5             30% of 35 is 10.5
2. 35 + 10.5 = 45.5 hours
3. He worked 45.5 hours in December
Ex. Dylan worked 35 hours in November. He has worked 30% more in December. How much did he work in December? 

Slide 11 - Diapositive

Percentage decrease
1. Calculate the percentage of the original value
2. Subtract this percentage from the original value
(3. Write your conclusion)


There is a pair of trainers in the sale. They were originally €60.
 They have 20% off. How much do I pay for them?

Slide 12 - Diapositive

There is a pair of trainers in the sale. They were originally €60.
They have 20% off. How much do I pay for them?

Slide 13 - Question ouverte

Percentage decrease
1. Calculate the percentage of the original value
2. Subtract this percentage from the original value
(3. Write your conclusion)


1. 20% of 60                        0.20 ⋅ 60 = 12.0                so 20% of 60 is 12

There is a pair of trainers in the sale. They were originally €60.
 They have 20% off. How much do I pay for them?

Slide 14 - Diapositive

Percentage decrease
1. Calculate the percentage of the original value
2. Subtract this percentage from the original value
(3. Write your conclusion)


1. 20% of 60                        0.20 ⋅ 60 = 12.0                so 20% of 60 is 12
2. 60 - 12 = 48

There is a pair of trainers in the sale. They were originally €60.
 They have 20% off. How much do I pay for them?

Slide 15 - Diapositive

Percentage decrease
1. Calculate the percentage of the original value
2. Subtract this percentage from the original value
(3. Write your conclusion)


1. 20% of 60                        0.20 ⋅ 60 = 12.0                so 20% of 60 is 12
2. 60 - 12 = 48
3. With the discount I pay €48 for the trainers.
There is a pair of trainers in the sale. They were originally €60.
 They have 20% off. How much do I pay for them?

Slide 16 - Diapositive

Practice
1. Increase €300 by 10%
2. Increase $80 by 75%
3. Decrease RP 220 by 15%

1. Increase £96 by 15%
2. Increase € 256 by 5%
3. Decrease € 72 by 20%
4. Decrease € 321 by 2%

Level 1                                                 Level 2

Slide 17 - Diapositive

Practice
1. €330
2. $140
3. RP 187


1. £110.40
2. € 268.80
3. € 57.60
4. € 314.58


Level 1                                                 Level 2

Slide 18 - Diapositive

Holiday
Louise needs some help to book her Winter holiday.

There are four possible destinations to choose from, but Louise wants to find the cheapest deal.

She wants to go away for 2 weeks. The holiday is for 2 adults and 2 children.

In pairs work out the cost of each holiday and decide which is the best value.



Slide 19 - Diapositive

Which destination should Louise choose?
A
Thailand
B
New York
C
Hawaii
D
Australia

Slide 20 - Quiz

Holiday 
Thailand - €2522.52

New York - €2563.60
Hawaii - €2541.90
Australia - €2521.26



Slide 21 - Diapositive

In class work
p. 189 : 9F               1, 3, 5, 7, 8abc
p. 190-191 : 9G             1, 3, 6
                                  




Slide 22 - Diapositive

Homework
Create your own percentage problem.

- the more complex your context and problem is, the better
- provide the correct answer + working out for your problem as well
- I will choose problems for tomorrows lesson

Slide 23 - Diapositive