# 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.

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?

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

where we get a research paper on Nano chemistry....?
what are the products of Nano chemistry?
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
I only see partial conversation and what's the question here!
what about nanotechnology for water purification
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
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
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