1TH/Vwo §5.2 Percentages

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

§5.2 Percentages

Question:

What is used in both situations?

Answer in next slide!

In both situations a ............. is used.

Answer:

A RATIO TABLE !

On the right you see     

an example of it.

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

+ pay attention to every little step

+ your teacher will explain this Task

+ soon you will do one yourself!

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:

Reminder:

When making the homework,

Make sure you produce a RATIO TABLE for every exercise!

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 in

Task 9:

Task 9:

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.

+ Skip 12

+ Later follows a new instruction. 

New instruction:

+ Up to now we calculated a percentage, in the table below.

+ However from exercise 15 on it's the other way around.

+ Now we will calculate the number, up!

+ Follow the coming example.

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:

You don't  have to make:  9, 12 and 16.

          

However:  MAKE A RATION TABLE FOR EVERY EXERCISE!!

+ check your work with the Solutionsbook

+ take pics 

+ send in in GC