# 3.2 Selection and computations

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1. The following activity is for your portfolio.

Look carefully at the assessment table before you begin – your teacher will allocate a code from 1 - 4 for the different sections.

Challenge!

1.1 Carry out a survey in your class and find out how many learners read which magazines. Write you information down in a table, e.g.

 Magazine You Time SA Runner Fair Lady Number of learners ................. ................ ................. .................

1.2 Now show the information by means of a pie diagram.

1.3 Answer the following questions:

a) Which magazine is the most popular?

b) Which magazine is read the least?

c) Which magazine is YOUR favourite?

Why?

BRAIN–TEASER!

Who am I?

a) If you subtract me from $\frac{1}{2}$ , you will get $\frac{3}{8}$

b) If you cut me into sixths, you will have $\frac{\text{24}}{6}$

c) If you double me, you will get 4 $\frac{1}{2}$

1. If you halve me, you will get $2\frac{1}{\text{12}}$
2. If you calculate $\frac{3}{4}$ of me, you will get 12

## To solve problems in context [lo 1.6.1]

Split up into groups of three. You will be given the necessary paper to work on. Remember to discuss the solutions amongst yourselves beforehand and then you can do them neatly on paper.

1. Mrs Mvusi buys 7 metres of material. If she wants to make each one of her four children a bright cushion for his or her room, how many metres of material can she use for each one? (All the cushions are of the same size.) Give each answer as a fraction.

2. Mr Muruvan buys 9 pieces of dry sausage that he wants to share equally among himself, his wife and their five children. What fraction of the sausage will each one get?

3. Grandpa Ben would like to divide R30 equally among his four grandchildren. What is the amount each one will get?

a) Did she divide it fairly?

b) What fraction does each person get?

c) Write your answer as an improper fraction:

1.3 Sketch the solutions to the following:

a) Divide eight fizzers equally between five children.

b) Divide five milk tarts equally between 12 guests.

1.4 Calculate the following:

a) Divide R5,00 equally between four children.

b) Divide 13 pies equally between eight learners.

## To use a series of techniques to do calculations [lo 1.10.5]

1. It is important for us to know how to key in ordinary fractions on a pocket calculator. This will help us find the answers to problems in no time.

Did you know?

If you want to show a fraction on the calculator, e.g. $\frac{5}{7}$ you must key in 5 ÷ 7 = .

1.1 How does the calculator show the following fractions? Write down what you key in.

a) $\frac{3}{5}$ ______________

b) $\frac{6}{7}$ ______________

c) $\frac{5}{8}$ ______________

d) $\frac{1}{\text{12}}$ ______________

e) $\frac{3}{4}$

BRAIN–TEASER!

There are seven cows in a camp. Isolate them by means of three fences so that each cow is in its own small camp.

Indicate with a coloured pencil crayon where you would put the fences.

## Assessment

 Learning outcomes(LOs) LO 1 Numbers, Operations and RelationshipsThe learner is able to recognise, describe and represent numbers and their relationships, and counts, estimates, calculates and checks with competence and confidence in solving problems. Assessment standards(ASs) We know this when the learner: 1.1 counts forwards and backwards fractions; 1.2 describes and illustrates various ways of writing numbers in different cultures (including local) throughout history; 1.3 recognises and represents the following numbers in order to describe and compare them: common fractions to at least twelfths; 1.5 recognises and uses equivalent forms of the numbers listed above, including: 1.5.1 common fractions with denominators that are multiples of each other; 1.6 solves problems in context including contexts that may be used to build awareness of other Learning Areas, as well as human rights, social, economic and environmental issues such as: financial (including buying and selling, profit and loss, and simple budgets); LO 5 Data handlingThe learner will be able to collect, summarise, display and critically analyse data in order to draw conclusions and make predictions, and to interpret and determine chance variation. We know this when the learner: 5.3 organises and records data using tallies and tables;

## Memorandum

ACTIVITY 1

1. 1.1 $\frac{1}{8}$ 1.2 $\frac{3}{\text{12}}$ = $\frac{1}{4}$

1.3 $\frac{3}{\text{12}}$ = $\frac{1}{4}$ 1.4 $\frac{6}{\text{10}}$ = $\frac{3}{5}$

1.5 $1\frac{5}{\text{10}}$ = $1\frac{1}{2}$ 1.6 $1\frac{3}{8}$

ACTIVITY 2

1. It is the same

2. 10 ; 5

7.1: 21

7.2; 20

• :300

7.4 :168

ACTIVITY 3

1. 1.1: 200 ml

1.2: 1 500 m

1.3: 300 g

1.4; $\frac{5}{6}$

1.5: 2 500 mm or 2,5 m or 2 $\frac{1}{2}$ m

BRAIN-TEASER!

a) $\frac{1}{8}$

1. 4
2. 2 $\frac{1}{4}$
3. 4 $\frac{1}{6}$
4. 16

1.4 a) R1,25 / 125c

1. 1 $\frac{5}{8}$

ACTIVITY 7

1.1 a) 3  5 = 0,6

1. 6  7 = 0,8571428
2. 5  8 = 0,625
3. 1  12 = 0,0833333
4. 3  4 = 0,75

#### Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
how did you get the value of 2000N.What calculations are needed to arrive at it
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