# 2.1 Division

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## To be able to do mental arithmetic [lo 1.10]

1. You already know how important it is to be able to do mental arithmetic. You also know how important it is to know your tables. Doing mental arithmetic and knowing your tables will help you do division correctly, too. Let us start right away! Do you also like dried sausage ("droëwors")? Work with a friend. Look closely at the two "sausage machines". The one who is first to give the answers is the fastest sausage maker!

Who won?

2. Work on your own and colour in according to the code: 4 = dark grey ; 5 = pink ; 6 = light grey ; 7 = black ; 9 = red.

3. Complete the tables:

 34 3.1 Divided by 3 4 5 6 7 8 9 Remainders 1 ............ ............ ............ ............ ............ ............
 61 3.2 Divided by 2 5 6 7 8 9 10 Remainders 1 ............ ............ ............ ............ ............ ............

4. Let us see how well you do in the following mental test. Complete it as quickly and accurately as you can:

 4.1 35 – 5 – 5 – 5 = ............ 4.11 108 – 12 – 12 – 12 = ............ 4.2 64 – 8 – 8 = ............ 4.12 72 – 9 – 9 = ............ 4.3 42 ÷ 7 = ............ 4.13 Halve: 612: ............ 4.4 54 ÷ 6 = ............ 4.14 Halve: 487: ............ 4.5 ............ ÷ 7 = 8 4.15 Halve: 1 036: ............ 4.6 ............ ÷ 12 = 6 4.16 ............ ÷ 9 = 4 4.7 28 ÷ 4 = ............ 4.17 ............ ÷ 8 = 6 4.8 280 ÷ 4 = ............ 4.18 60 ÷ ............ = 5 4.9 280 ÷ 40 = ............ 4.19 36 ÷ ............ = 4 4.10 2 800 ÷ 40 = ............ 4.20 3 600 ÷ 90 = ............

DID YOU KNOW?

Division is the inverse of multiplication.

Thus: 5 × 3 = 1515 ÷ 3 = 5 en15 ÷ 5 = 3

When I want to check a division sum, I multiply. When I check a multiplication sum, I divide

## [lo 1.12.1]

1. Now use your knowledge of the "inverse" to complete the following:

1.1 If 26 × 17 = 442, then 442 ÷ 17 = ................ and 442 ÷ ................ = 17

• If 24 × 30 = 720, then 720 ÷ ................ = 24 and 720 ÷ 24 = ................

DID YOU ALSO KNOW?

When we divide, we do the following:

REPEATED SUBTRACTION

12 ÷ 3 = 12 – 3 – 3 – 3 – 3 = 4

GROUPING

12 ÷ 3: We must divide 12 into 3 equal groups

DIVISION

12 ÷ 3: We must divide 12 equally between 3

123

## To recognise and represent numbers and to describe and compare them [lo 1.3]

1. Let us do revision. Do you remember what happens when we divide any number by 1? Work with a friend and find the answers to the following:

1.1 5 ÷ 1 = .................................. 1.2 86 ÷ 1 = ............................

1.3 359 ÷ 1 = .............................. 1.4 4 625 ÷ 1 = .......................

1.5 32 174 ÷ 1 = .........................

2. Write down a rule for dividing by 1.

BRAIN-TEASER!

If 5 ÷ 1 = 5 and 86 ÷ 1 = 86, then:

1 ÷ 5 = .........................

1 ÷ 86 = .........................

1 ÷ 359 = .........................

1 ÷ 4 625 = .........................

Thus, if 1 is the dividend, then the answer is always a...........................................

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
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?
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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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