# 2TH §7.6 Mixed exercises.

§7.6 Mixed exercises
Lot of Recap follows! And some questions too.

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Slide 1: Tekstslide
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In deze les zitten 26 slides, met interactieve quizzen en tekstslides.

Lesduur is: 50 min

## Onderdelen in deze les

§7.6 Mixed exercises
Lot of Recap follows! And some questions too.

#### Slide 1 -Tekstslide

Recap: Factor
A factor is the number you multiply an original amount by, to get the new amount.

You should be able to calculate the factor for a given increase/decrease in percent and also the other way around.
Drawing a table can help!

Recap: Factor

#### Slide 3 -Tekstslide

Exercise 1:           ANS

What factors belong to:
1. the increase of 21 % and
2. the decrease of 32 % ?

#### Slide 4 -Tekstslide

Which factors belong to
1. an increase of 21 % and
2. a decrease of 32 % ?
A
121 and 68
B
0.79 and 1.32
C
1.21 and 0.68
D
79 and 132

#### Slide 5 -Quizvraag

Explanation:
1. an increase of 21 % means:
100 % + 21 % = 121 %   so  factor 1.21
2. a decrease of 32% means:
100 % - 32 % = 68 %  so factor 0.68

#### Slide 6 -Tekstslide

Recap: Factor

The key word here
is 'change'
(in percentage)!

#### Slide 7 -Tekstslide

Exercise 2: the same way as number 1
What change in percentage corresponds to a factor
of 0.76 ?
A.  a 24 % decrease   B. a 24 % increase
C. a 76 % decrease    D. a 34 % decrease

#### Slide 8 -Tekstslide

Change in % if factor is 0.76 ?
A
a 24 % decrease
B
a 24 % increase
C
a 76 % decrease
D
a 34 % decrease

#### Slide 9 -Quizvraag

Explanation:
factor  0.76  corresponds to 76 % of the old amount
so  100 % - 76 % = 24 %
Conclusion:
multiplying by factor 0.76 means that 24 % is taken off!

#### Slide 10 -Tekstslide

Recap: Factor

The key word here is:
'change' (in percentage) !

#### Slide 11 -Tekstslide

Exercise 3: again in the same way.
What change in percentage corresponds to a factor of 3 ?           A. 400 %               B. 300 %
C. 130 %              D. 200 %

#### Slide 12 -Tekstslide

What change in %
corresponds to a factor of 3 ?
A
400 %
B
300 %
C
130 %
D
200 %

#### Slide 13 -Quizvraag

Explanation:
If you do:                  x 3,
then  you get:
100 %  x  3  =  300 %
So the change is:      300 % - 100 % = 200 % more!

#### Slide 14 -Tekstslide

Those nasty percentages ......
These little fellas really made us sweat!

#### Slide 16 -Tekstslide

§7.3 Recap: Exponential formulas
A table or graph shows exponential growth if the bottom row (=vertical variable) is multiplied by the same number everytime the top row/horizontal variable increases by 1. (read this at least two times!)

An exponential formula has the form
b is the initial amount, the value of y when x = 0, because
g is the growth factor, the number you multiply with.
y=bgx
g0=1

#### Slide 17 -Tekstslide

Recap: MAKING Exponential formulas
First we CHECK from the TABLE IF there is exponential growth.
Only the FORMULA is made.  Just have a good look and be amazed:

#### Slide 18 -Tekstslide

Recap: Growth factor
If the growth factor is between 0 and 1,
the graph is decreasing.

If the growth factor is 1,
the graph is constant

If the growth factor is more than 1,
the graph is increasing.

#### Slide 19 -Tekstslide

Recap: Standard notation
A number in standard (=scientific) notation is a number between 1 and 10 multiplied by a power of 10.

The power of 10 tells you how many places you should move the decimal point to the right (positive power) or to the left (negative powers).

You should be able to write normal numbers in standard notation and the other way around.

#### Slide 20 -Tekstslide

Recap: Standard notation
Write these numbers in standard notation. Round the first number to two decimal places.
Next slides will provides you with the answers, later on.
timer
1:30

#### Slide 21 -Tekstslide

Recap: Standard notation
Write these numbers in standard notation. Round the first number to two decimal places. These tiny numbers are there to help you counting!

#### Slide 22 -Tekstslide

Recap: Standard notation
Write these numbers in normal notation.
COPY the two exercises and then write down the answers.

timer
1:15

#### Slide 23 -Tekstslide

Recap: Standard notation
Write these numbers in normal notation.

#### Slide 24 -Tekstslide

Homework time
Do §7.6 Mixed exercises: Exercises 45 + 49