# 1TH/Vwo §8.5 multiplying fractions

§8.5 Multiplying fractions
After   +       and        -     we now look at
the operation:       x   !
By the way, this is a pretty long LessonUp.
The Homework however is only 3 exercises.

1 / 34
Slide 1: Tekstslide
WiskundeMiddelbare schoolhavo, vwoLeerjaar 1

In deze les zitten 34 slides, met interactieve quizzen en tekstslides. Lesduur is: 30 min

## Onderdelen in deze les

§8.5 Multiplying fractions
After   +       and        -     we now look at
the operation:       x   !
By the way, this is a pretty long LessonUp.
The Homework however is only 3 exercises.

#### Slide 1 -Tekstslide

First we multiply a fraction by a whole number:

32
timer
1:00
x 33 = ...

solution:

#### Slide 6 -Tekstslide

another one for you:

3/13 x 52 = ....
timer
0:25
A
10
B
9
C
14
D
12

Solution:

#### Slide 10 -Tekstslide

Finally it's
Fraction times Fraction ...

#### Slide 12 -Tekstslide

2 Important points:
.                        and               .

#### Slide 13 -Tekstslide

an even more important point is this:
COMMON MISUNDERSTANDING; somebody tries to tackle the task below :
' Wait a sec, the new denominator is 14 x 4, but then it's still a long way....

x            =         x          =                          x                         ??? I am at a loss...'
1413
43
5652
5642
.............
...............

#### Slide 14 -Tekstslide

Why does this method really suck?

#### Slide 15 -Woordweb

SOLUTION:

When multiplying fractions with unequal denominators,
you don't have to make them equal!!
Watch the next slides that show how simple it really is!

3/8 x 3/8 = ...
timer
0:25
A
9/8
B
9/64
C
6/16
D
3/64

Solution:

#### Slide 23 -Tekstslide

Fotovraag: first work it out in your Notebook, take a pic and send in in next slide!

#### Slide 24 -Tekstslide

2/7 + 1/7 x 1/2 = ......
timer
1:00

Solution:

#### Slide 26 -Tekstslide

Now it's time for a complicated one:

Think about HOW to WORK it out!
After that we look at the solution.

#### Slide 27 -Tekstslide

This is the Solution:

#### Slide 28 -Tekstslide

For example this one.                                   You might think:
2  x  3 = 6      and                 x          =

So the final answer is:        6   +        =   6                 However this is WRONG!

21
41
81
81
81

#### Slide 29 -Tekstslide

Let's look back at the previous slide for a sec to see if both methods are good!

#### Slide 30 -Tekstslide

Fotovraag:
again work it out in your Notebook first and then send it in.

#### Slide 31 -Tekstslide

1 1/8 x 1 1/3 = ......
timer
1:30

Solution:

Homework: