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Having fun with pocket calculators and negative numbers

Educator section


6. a) get dressed and eat

clean different rooms in the house

order in which you do your homework

learners gives own answers

  1. first draw money and then do your shopping

fisrt learn your work and then write a test

cover books; plastic last

throw petrol in first and then ride

learners give own answers

8. a) 66

  1. 0
  2. 9
  3. 223
  4. 153

Leaner section


Activity: fun with the pocket calculator [lo 1.9.2


If you do not know the sequence in which you have to do calculations, the pocket calculator will not be of any help to you - it will actually help you out of the frying pan into the fire!

Discuss the following:

a) Does it matter if you put the milk into the teacup before pouring the tea, or the tea before the milk?

b) Do you brush your teeth before breakfast or do you eat first and then brush your teeth?

c) Give examples of where the sequence in which you do things does not matter.

d) Give examples of where the sequence matters/is important.


We work from left to right when we do repeated addition and subtraction.

e.g. 20 – 5 + 12 – 5 – 2 = 20

We work from left to right for repeated multiplication and division.

e.g. 6 × 3 ÷ 2 = 9

In the case of mixed calculations, the sequence is:

( ) brackets

8. Use your pocket calculator to find the answers to the following:

a) 100 – 4 × 5 – half of 28


b) 26 × 54 – 54 × 26

______________________________________________________________c) 200 ÷ 20 + 285 ÷ 95 – 8 + 4

______________________________________________________________d) 382 – (129 + 31) + one third of 3


e) (65 – 15) × 3 + 21 ÷ 7



Learning Outcome 1: The learner will be able to recognise, describe and represent numbers and their relationships, and to count, estimate, calculate and check with competence and confidence in solving problems.

Assessment Standard 1.9: We know this when the learner uses a range of techniques to perform calculations including:

1.9.2: using a calculator.

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
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.
what is the actual application of fullerenes nowadays?
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.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
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.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Mathematics grade 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11075/1.1
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