1TTO §6.2 Percentages

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

§6.2 Percentages

Question:

What Method is used in both situations?

Answer in next slide!

Answer to question:

using a ratio table !

video

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!

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.

   (this exercises is also in your book, p.180)

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 exercise 15 on it's the other way around.

+ Now we will calculate the numbers! 

+ Follow the coming example.

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.

HOMEWORK:

In this way do:

+ check your work with the Solutionsbook