1Tvwo §9.1 Shortening formulas

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 1

§ 9.1 Shortening formulas

This baby doesn't seem too happy with his formula.

Let's do the INTRODUCTION of the paragraph first.

§ 9.1 Shortening formulas

Formulas are not new to you. 

For example:  length = days x 10 + 25  (for the growing process of a plant)

It is pleasant when the formula is made as short as possible.

That's what we're going to do in this Paragraph!

But first things first: the INTRODUCTION of the paragraph.

Let's read it together.

Question 1:

What exactly do you need

to do?

Question 2:

What is the answer to 

the question in the

text?

After this exciting intro...

we will do exercise 3 together.

Let us do exercise 3 on p.95 in our Notebook.

Before we do this task together, we study the WORDS in it!

A.  think about the meaning of:    'lorry', 'ferry', 'lorry driver'  and 'fare'

B.  DISCUSS with your neighbor(s) the meaning of:  

  'lorry', 'ferry', 'lorry driver'  and 'fare'

So, compare the meaning you found with your neighbor.

Do you think the same about these words?

the meaning of:   

 'lorry'  -  vrachtwagen

 'ferry' - boat or ship

 'lorry driver'  - the driver of the lorry

  'fare' - money paid for a journey (on public transport)

TASK: 

Before we make the formula, answer this question:

If the driver has a lorry of 15 meters, what does he have to pay for the ferry?

Answer in next slide.

If the driver has a lorry of 15 meters, what does he have to pay for the ferry?

1. 302 euros
2. 50 euros
3. 30 euros
4. 35 euros

In Chemistry (scheikunde) Water is:   

But this you can also understand as:

from the letter H to O.

Isn't that awfully funny?                     

H​2​​

O

Write down your Formula in your Notebook.

Remember that a formula has an 'equals sign'! 

 So '=' has to be in it.

Remember: in this formula you can fill in any number of meters and the result (= outcome) will be the price you have to pay!

Formula for the total amount the driver has to pay

SOLUTION:

amount =  length in meters  x  2 + 20

We can shorten 'length in meters' in 'l' and 'amount' in 'a'.

Made shorter this formula becomes:

a = l x 2 + 20    or:      20 + 2 x l = a

So there is some room for variation!

Now do question 3b

Do this in your Notebook. Also key it in the next slide.

The formula we have found at 3a)       a = l x 2 + 20

New formula:

1. 1.80 x l + 20 = a
2. l x 1.80 + 22 = a
3. 2 x l + 22 = l
4. a x 1.80 + 22 = l

Solution:    The formula we have found at 3a) a = l x 2 + 20

n=7f+4

There is a difference between ....

The letter       and the multiplication sign: x !

The letter       is a variable, that stands for a number, that you can choose yourself. 

For example:     = 6 +         If you choose 4 for     , then     = 6 + 4 = 10

However in:         6 x 8 = 48,   the x  means that you are multiplying.

x

x

x

x

y

y

By the way ....

The reason to leave out the x in, for example:

y = 3 x     = 3  

is that the symbols for x  and for the letter       ,

are that similar, that it gets confusing!

6 x             = 6     

x

x

m

m

In exercise 6 there are a few new (?) words:

'staff and maintenance'.

Answer in the next slide the meaning of

'staff and maintenance'.

'staff and maintenance' means .....

Homework

§9.1, Do exercises 4, (S)5, 6, C1, C2

Afterwards, check your answers with the solutionsbook in Teams.