1TTO §6.2 Percentages

• Wiskunde
• Middelbare school
• havo, vwo
• Leerjaar 1

§6.2 Percentages

Let's do a Task together, using a Ratio Table.

+ pay attention to every little step

+ now and then you are asked to give an answer

This calls for a Ratio Table! See calculation next slide

Give the correct answer in the next slide!!!

Watch what a subtle role is played by the number '1' !

Going from 20 to 6 directly is more difficult, 

so we go from 20 to 1 to 6, which is much easier!

The percentage of pupils is ...

1. 25
2. 35
3. 30
4. 40

summarizing:

Do the following exercise.

+ Open your Notebook

+ Take your pen, pencil and geo triangle

+ Watch the next slide! 

+ Try the exercise yourself.

  

Apply what you just learned:

Now work for yourself on §6.2 (= homework).

+ Make RATIO TABLES for every exercise!

+ No calculator; work it all out on paper and in your head.

+ Later follows a new instruction. 

New instruction:

+ Up to now we calculated a percentage.

+ However from next exercise on it's the other way around.

+ Now we will calculate the numbers! 

+ Follow the coming example.

Copy the table in your notebook and fill it in.

Give the correct answer in the next slide

1. 100
2. 90
3. 80
4. 85

Again watch the vital part that is played by the number '1'!

Now it is on the bottom line(!) and 

it helps us going from 100 to 15 in a simple way.