1TTO §7.1 From description to formula

§7.1 From description to formula
First there comes an example.
See next slide, showing an exciting nature event.
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Slide 1: Tekstslide
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In deze les zitten 19 slides, met interactieve quizzen en tekstslides.

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§7.1 From description to formula
First there comes an example.
See next slide, showing an exciting nature event.

Slide 1 - Tekstslide

Slide 2 - Tekstslide

a. We read this text together.
b. Answer the question below in the next slide.

Slide 3 - Tekstslide

Roughly how far away is the thunderstorm?
A
2 km
B
2 + 2/3 km
C
2.5 km
D
3 km

Slide 4 - Quizvraag

Solution:
It takes the thunder 3 seconds to travel 1 km.
So if you hear the thunder after 8 seconds, then it is
8 : 3 = 2  2/3 km away.
However, because the question said 'roughly' (ongeveer) also
2.5 km is a good answer.

Slide 5 - Tekstslide

A rule in words about this is:
If you divide the time in seconds the thunder takes to reach you by 3, you get the distance in km.

Slide 6 - Tekstslide

This Rule in Words is changed into a Formula now:
If you divide the time in seconds the thunder takes to reach you by 3, you get the distance in km. (=Rule in Words)

time in seconds : 3 = distance in km (= Formula)

Slide 7 - Tekstslide

What does a Formula have, but a Rule in Words does not?

Slide 8 - Woordweb

Solution:
A Formula has arithmetic symbols like:
+           -              x      and      :  
(What is Described(=beschreven) only in a Rule in Words, is made into a Calculation in a Formula.)

Slide 9 - Tekstslide

Slide 10 - Tekstslide

Let's make a Formula now!
In the next exercise you get some information.
You are asked 
A) to make a Formula and then 
B) to make a Calculation with it.

Slide 11 - Tekstslide

Slide 12 - Tekstslide

Formula .... ?

Slide 13 - Woordweb

The correct Formula is:

number of balls x 60 + 250 = weight,  or
250 + number of balls x 60 = weight,  or 
weight = number of balls x 60 + 250
So you see that there are more ways to write it down!

Slide 14 - Tekstslide

Now answer this one, using the Formula you just made!

Slide 15 - Tekstslide

Calculate the weight of a box containing 6 balls.
The Formula is:
number of balls x 60 + 250 = weight
A
600
B
590
C
580
D
610

Slide 16 - Quizvraag

Solution:

Slide 17 - Tekstslide

Summarising:
Sometimes you have a Description or a Formula in Words.
You can change this into a Formula.
In a Formula you can fill in a given number, to get an outcome.
Like we just did.

Slide 18 - Tekstslide

Homework time
Time to do 0f §7.1 now: 6, 7 and 8.

Don't forget to 
+ check with the Solutionsbook    

Slide 19 - Tekstslide