# 1TH/vwo §8.2, §8.3 and §8.4 once more.

Some more practice with §8.2, 3 and 4
Nothing new, this time.
This makes sense, as doing adding and subtracting with
positive and negative numbers is quite tricky!
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Slide 1: Slide
WiskundeMiddelbare schoolhavo, vwoLeerjaar 1

This lesson contains 18 slides, with interactive quizzes, text slides and 1 video. Lesson duration is: 45 min

## Items in this lesson

Some more practice with §8.2, 3 and 4
Nothing new, this time.
This makes sense, as doing adding and subtracting with
positive and negative numbers is quite tricky!

#### Slide 2 -Slide

This lesson ...
+ you'll get a lotta time to work on with the SUMMARY/EXTRA EXERCISES
+ a Movie about adding and subtracting with positive and negative numbers
+ then follows a short look back at §9.2 and §9.3

#### Slide 4 -Video

6 + 7 = 13
The simplest type of exercise.
A positive number, 7, is added to a number. This makes the result greater than the start:     13 is greater than 6.

#### Slide 5 -Slide

7 + -4 = 3
A NEGATIVE number is added to a number.
Now the result is less:  3 is less than 7.

#### Slide 6 -Slide

Subtracting 1:
8 - 5 = 3
A Positive number is subtracted from a number.
the result is less:   3 is less than 8.
Beware of the last type, next slide!

#### Slide 7 -Slide

Subtracting 2:
6 - -5 = ....
This is the most exciting type!
If a negative number is subtracted, it has the same effect as adding a positive number: 6 - -5 = 6 + 5 = 11

#### Slide 8 -Slide

Once more the whitch's cauldron:
6 - -5 = ....
Suppose the start temperature in the cauldron
is 6 degrees. Now she takes out 6 Cold Blocks.
then it gets warmer in the cauldron!
So taking out cold blocks does the same as putting in hot blocks.
So: 6 - -5 = 6 + 5 = 11

-5 --6 = ...
A
-1
B
11
C
1
D
-11

--6 -7 = ...
A
13
B
1
C
-1
D
-13

6 + -3 x -4 =
A
-12
B
18
C
-6
D
-1

6 + -3 x -4 =...
6 + 12 = 18

#### Slide 15 -Slide

Homework time:
Finish the homework now.
Also CHECK it with the SOLUTIONSBOOK
Make a few pics and send them in in GC

#### Slide 16 -Slide

+ §9.2 and §9.3, that we just discussed!