# 1TTO §8.4 Adding and subtracting fractions

Fractions??!
Next slide shows you some of those little fellas!
Just lean back and let yourself be informed.

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Slide 1: Slide
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This lesson contains 24 slides, with interactive quizzes and text slides. Lesson duration is: 30 min

## Items in this lesson

Fractions??!
Next slide shows you some of those little fellas!
Just lean back and let yourself be informed.

#### Slide 2 -Slide

A fraction has a ......   and a ....... see below!
The number above is called:   the numerator ( = teller). It tells us: HOW MANY?
The number below is called:    the denominator (= noemer). It tells us the
TOTAL of the numbers and it's also the NAME.
4 = numerator     and
5 = denominator
54

#### Slide 3 -Slide

Finally don't forget to SIMPLIFY the answer, if possible!

#### Slide 7 -Slide

However ..... is it always just a piece of cake?

#### Slide 8 -Slide

When is it a bit more work to add or subtract fractions?
What kinda fractions are at stake then?

#### Slide 9 -Mind map

With 'common' denominators 'equal' ones are meant!

3/4 - 2/5 = ....

#### Slide 13 -Mind map

explanation:
the new denominator becomes         4 x 5 = 20 now!

-                     =                           -                            =
43
52
2015
208
207

#### Slide 15 -Slide

But .........
How to add or subtract fractions like:

3           and      6          ?

Next slide explains more.
65
43

#### Slide 17 -Slide

The following slide ...
as it deals with tricky fraction facets!
Unequal denominators and more
trouble...

#### Slide 19 -Slide

How to do it?! Think about common denominators, of course.
What is the final outcome?

5 2/3 + 7/11 =

Homework time