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BRAIN-TEASER!

Calculate the following in the same way as the Egyptians did thousands of years ago:

15 × 241

  • Is there an easier way of doing it? Discuss this with your friend. Check your answer with a calculator.

DID YOU KNOW?

Thus we can also make use of DOUBLING when we want to multiply:

2 × 280 = (200 + 200) + (80 + 80)

= 400 + 160

= 560

Activity 5:

To use a series of techniques to do computations with whole numbers [lo 1.10.4]

1. If you looked carefully at the example above, you would have seen that this method of doubling differs from that of the Egyptians. Can you calculate the following by doubling it in exactly the same way?

1.1 2 × 1 430 =

1.2 2 × 2 315 =

2. We would very much like to use the shortest possible method in Mathematics, because it saves a lot of time, trouble and paper. Calculate the product again by doubling, but this time use a shorter method if you can.

2.1 2 × 14 820 =

2.2 2 × 36 947 =

3. There is another technique that you can use to calculate the product. You can double and halve ! This makes it easier to multiply with the “big” numbers. Look carefully at the following:

126 × 5= 63 × 10 (halve 126 ; double 5)= 630

Can you find the following answers by doubling and halving ?

3.1 50 × 24 3.2 5 × 346

BRAIN-TEASER!

Can you fill in the missing numbers/factors WITHOUT using your calculator?

48 × 12 = 576 64 × 10 = 640
........... × 24 = 576 32 × ........... = 640
12 × ........... = 576 ........... × 40 = 640
6 × ........... = 576 8 × ........... = 640
........... × ........... = 576 ........... × ........... = 640

Did you discover a pattern?

Activity 6:

To calculate by using selected computations [lo 1.9.2]

1. Now let us look at multiplication with multiples of 10 and 100. As we work through the examples, you will see that there are certain rules that you must follow in order to calculate the product. If you apply these rules, you will be able to calculate the answers without doing long computations on paper. Work with a friend and write down the product of the following:

1.1 10 × 6 = ......................... ; 10 × 60 = ......................... ;

10 × 600 = ......................... and 10 × 6 000 = .........................

1.2 10 × 9 = ......................... ; 10 × 90 = ......................... ;

10 × 900 = ......................... and 10 × 9 000 = .........................

1.3 10 × 15 = ......................... ; 10 × 150 = ......................... ;

10 × 1 500 = .........................

1.4 10 × 26 = ......................... ; 10 × 260 = ......................... ;

10 × 2 600 = .........................

Can you now write down a rule for multiplying any number by 10?

Does this “work” for 0,5 × 10?

2. Let us look at multiplication with multiples of 100. Work with the same friend and write down the product of:

2.1 100 × 8 = ......................... ; 100 × 80 = ......................... ;

100 × 800 = .........................

2.2 100 × 13 = ......................... ; 100 × 130 = ......................... ;

100 × 1 300 = .........................

2.3 100 × 27 = ......................... ; 100 × 270 = ......................... ;

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
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
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
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
Brian Reply
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?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
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 ?
Bob Reply
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?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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 5. OpenStax CNX. Sep 23, 2009 Download for free at http://cnx.org/content/col10994/1.3
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