1TTO §8.4 Multiplying and division PTI June24

1GHJK 
It is good to realise that x  and  :  are each others reverse!
For example:
48 : 8 = 6,  because 6 x 8 = 48 !
In this LessonUp you will get
+ new Information and
+ also quite a few short Tasks,
    to Practise this new Information.
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Slide 1: Slide
WiskundeMiddelbare schoolhavo, vwoLeerjaar 1

This lesson contains 23 slides, with interactive quizzes and text slides.

time-iconLesson duration is: 30 min

Items in this lesson

1GHJK 
It is good to realise that x  and  :  are each others reverse!
For example:
48 : 8 = 6,  because 6 x 8 = 48 !
In this LessonUp you will get
+ new Information and
+ also quite a few short Tasks,
    to Practise this new Information.

Slide 1 - Slide

Remember the woman with the soup and drinks.
Once upon a day she wants to work more efficiently
with her cold and hot blocks.
She wants to put in or take out MORE temperature blocks
IN ONE GO!
 For this she uses a BUCKET.
This is what this § is about.

Slide 2 - Slide

When you add or remove a larger number of blocks in one go:
Think about this and answer in the next slide:

You add a bucket of 6 cold blocks four times.
Does the temperature rise or fall?
By how many degrees?

Slide 3 - Slide

Adding a buckets of 6 cold blocks
4 times makes the temperature in the cauldron ...
A
rise
B
fall
C
stay the same

Slide 4 - Quiz

Answer:
Adding COLD BLOCKS makes the temperature fall.
NEW QUESTION: By how many degrees does it fall?
Remember: she adds 6 cold blocks 4 times!
Answer in the next slide!

Slide 5 - Slide

Adding 6 cold blocks 4 times makes the temperature fall by ... degrees.
A
24
B
-24
C
6
D
-6

Slide 6 - Quiz

SOLUTION:
The temperature gets lower, of course!
However, it falls by 24 degrees and not by -24 degrees.
In other words: is gets colder by 24 degrees.

Slide 7 - Slide

What happens to the temperature if 3 Cold Blocks are REMOVED 5 times?
Think about it carefully.
Answer in the next slide again.

Slide 8 - Slide

What happens to the temperature if 3 Cold Blocks are REMOVED 5 times?
A
it falls by 3 degrees
B
it rises by 3 degrees
C
it falls by 15 degrees
D
it rises by 15 degrees

Slide 9 - Quiz

removing 5 times 3 cold blocks:
Solution:
This is a bit tricky!
Removing cold blocks makes it LESS COLD  in the kettle.
out 5 times three cold blocks = 
- 5  x  -3 => it gets 5 times less cold because you remove cold blocks
So it gets 5 x 3 = 15 degrees WARMER!

Slide 10 - Slide

Question 1: What should be filled in in the 1st line?
Question 2: What mistake was made in the 2nd line? ('removed 6 times .......')

Slide 11 - Slide

Above you see the Basic Rules for Multiplying with
Positive and Negative Numbers.
Realise that you can always relate all these Calculations
to:     Hot and Cold Blocks in a number of Buckets, that are added or removed from the kettle!

Slide 12 - Slide

The reverse of multiplying is ....
dividing!

Slide 13 - Slide

Key in your answer in the next slide!

Slide 14 - Slide

24 : -8 = -3, because ....
(make the multiplication!)
A
3 x -8 = -24
B
-3 x 8 = -24
C
-3 x -8 = 24
D
3 x 8 = 24

Slide 15 - Quiz

                       Solution:
                       -3 x -8 = 24

Slide 16 - Slide


In this way, we can make Basic Rules for all 4 types of 
divisions (=delingen) with positive and negative numbers!
See next slide.

Slide 17 - Slide

Slide 18 - Slide

Think about it.
Key in your answer in the next slide!

Slide 19 - Slide

-18 : -9 = ......
because ..... x ..... = .....

The Numbers to be filled in are:
A
-2, -2, 9, 18
B
-2, -2, -9, -18
C
2, -2, -9, 18
D
2, 2, -9, -18

Slide 20 - Quiz

We just learned that:
 a negative number divided by a negative number is a positive number.
So            - 18 : -9 = 2, because 2 x -9 = -18  !

Slide 21 - Slide

Homework:

Slide 22 - Slide

Evaluation

Slide 23 - Slide