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Mathematics

Decimal fractions

Educator section

Memorandum

  • a) 41c
  1. 42 1 2 size 12{ { { size 8{1} } over { size 8{2} } } } {}
  2. 44c
  • Rounding off

11.3.1 a) Look at the 2 nd digit after comma (100ths)

If 5, 6, 7, 8, 9: 10ths – digit 1 more

If 4, 3, 2, 1, 0: 10ths – digits remains the same

Replace everything after 10ths with noughts

  1. Look at 3 rd digit after comma

If 5, 6, 7, 8, 9: 100ths – digit 1 more

If 4, 3, 2, 1, 0: 100ths – digit remains the same

Replace everything after 100ths with noughts

  1. Look at 4 th digit after comma

If 5. 6, 7, 8, 9: Thousandths 1 more

If 4, 3, 2, 1, 0: Thousandths temain the same

Replace everything after 1 000ths with noughts

11.4 a) 4,5

9,9

5,3

7,6

52,6

88

11.4 b)

6,41 8,60 7,26 9,49 5,03 6,29

11.4 c) (i) (ii)

(iii) (iv)

  • (vi)

12.2 a) 11

  1. R406
  2. 6
  3. 5
  4. R327
  5. 8
  6. 9
  7. 14
  8. 448
  9. 1 390

Leaner section

Content

Activity: decimal fractions and rounding off [lo 1.4.2, lo 1.7.1]

11.1 DECIMAL FRACTIONS AND ROUNDING OFF

Work together with a friend. Look at the sketches. What does one potato cost in each case?

11.2 Round off the following to the nearest whole number. Write down the corresponding letter and see what word is hiding away.

B D E F G I K
39 149 7 236 38 6 17
L M N O R S T U
237 15 35 16 8 150 3 4

a) 8,047

b) 15,51

c) 3,7

d) 35,236

e) 149,089

f) 6,4

g) 35,09

h) 38,456

i) 15,912

j) 236,199

k) 235,89

What is your answer? ...........................................................................

11.3.1 Work in groups of three. Formulate rules/methods for the following:

a) Rounding off to one decimal place (tenths):

b) Rounding off to two decimal places (hundredths):

c) Rounding off to three decimal places (thousandths):

11.3.2 Compare your answers with those of the rest of the class.

11.4

a) Complete the following flow diagram:

b) See if you can complete the table correctly:

Number 4,368 6,411 8,599 7,255 9,493 5,034 6,286
Rounded off to 2 decimal places 4,37 ............. ............. ............. ............. ............. .............

c) Round off the following to 3 decimal places. Draw a circle around the correct answer:

12.1 Do you still remember?

1 000 ml = 1 litre

1 000 g = 1 kg

1 000 kg = 1 tonne

1 000 litres = 1 k

1 000 m = 1 km

100 c = R1,00

12.2 Fill in the missing answers:

e.g. 3 521 mm to the nearest m = 4 m

a) 11 296 mm to the nearest m = ......................... m

b) R406,38 to the nearest rand = R.........................

c) 6 455 litre to the nearest kl = ......................... kl

d) 4 823 kg to the nearest tonne = ......................... t

e) 32 687 c to the nearest rand = R.........................

f) 8 388 g to the nearest kg = ......................... kg

g) 8 630 m to the nearest litre = ......................... litres

h) 14 277 m to the nearest km = ......................... km

i) R4,4839 to the nearest cent = ......................... c

j) R13,9021 to the nearest cent = ......................... c

Assessment

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 1.4 We know this when the learner recognises and uses equivalent forms of the rational numbers listed above, including:

1.4.2 decimals;

Assessment Standard 1.7: We know this when the learner estimates and calculates by selecting and using operations appropriate to solving problems that involve:

1.7.1 rounding off numbers to at least one decimal place.

Questions & Answers

What is scarcity.
Npoanlarb Reply
when there is adequate resources
Fiona
why our wants are limited
Npoanlarb Reply
nooo want is unlimited but resources are limited
Ruchi
and do to that there occurs scarcity and we have to make choice in order to have what we need if need be I will explain more
Madara
our wants are not limited but rather the resources
Moses
as we know that there are two principle of microeconomics scarcity of resources and they have alternative uses...
Ruchi
yes .....
Mathias
because our resources are limited./we have a limited resources.
Ijeoma
what is demand
Thank Reply
demand is something wt we called in economic theory of demand it simply means if price of product is increase then demand of product will decrease
Ruchi
inverse relationship between demand and price
Ruchi
in microeconomic
Ruchi
demand is what and how much you want and what's your need...
Shikhar
how can one be so with economics even while you have less knowledge in mathematics.
OKORO Reply
why is it that some products increases everyday by day
Chiamaka Reply
because demand is increase
Ruchi
because demand is increase
Patience
but how demand increases?
Aziz
Because of the Marketing and purchasing power of people.
AmarbirSingh
but how could we know that people's demands have increased everyday by day and how could we know that this is time to produced the products in the market. Is any connection among them
yaqoob
for normal good people demand remain the same if price of product will increase or not
Ruchi
see that some product which increases day by day is comes under normal good which is used by consumer
Ruchi
Seems hot discussing going here
Shamamet
If there are less products demand starts to increase for those products
Shamamet
Economics is really interesting to learn ....
Shamamet
see there is Inferior goods ands normal goods inferior good demand is rarely increase whereas as we talk about normal good demand will absolutely Increase whether price is increase or not
Ruchi
and demand for normal goods increase cause people's income as a while increases time to time
Abhisek
and it might also be that the cost of raw materials are high.
ATTAH
may be
Ruchi
obviously because demand is increasing.....and price is getting low.....
Shikhar
hmmm there is inverse relationship between demand and price
Ruchi
This is because the supply of those products in relation to raw materials are decreasing and they are also necessities. This crate shortage in the market, so sellers will rise the prices of those products.
Abdul
Importance of economics
Odunayomi Reply
the nature and significance of economics studies
Deborah
What is demand
Shuaib Reply
deman is amount of goods and services a consumer is willing and able to buy or purchase at a given price.
Sainabou
the willingness and ability of a body to purchase goods nd servicesbis called demand ,so if she/has ability but doesn't have willingness it's not a demand same if she or he has willingness but doesn't has ability it's not a demand too
Gul
Demand refers to as quantities of a goods and services in which consumers are willing and able to purchase at a given period of time and demand can also be defined as the desire or willingness and backed by the ability to pay.
Fadiga
Yeah
Mathias
What is Choice
Kofi
Choice refers to the ability of a consumer or producer to decide which good, service or resource to purchase or provide from a range of possible options. Being free to chose is regarded as a fundamental indicator of economic well being and development.
Shonal
choice is a act of selecting or choosing from the numerous or plenty wants.
Fadiga
demand is want and it is also what you need and able to afford a particular period of time... because demand changes with time.
Ijeoma
Demand refers to the ability of the consumer to pay for a particular product at a given price
Abdul
how does consumer make profit
Clifford Reply
by buying goods in bulk.
Ijeoma
Compare and contract the function of commercial bank and the central bank of Nigeria
Akwi Reply
what do think is the difference between overhead costs and prime cost
Abdoulkarim
what is economics
Mohamed Reply
economics is a social science that study's how resources can be used to produce goods and services for society
Nathan
Economic is a science which studies human behavior as a relationship between ends and scares means which have alternatives uses or purposes.
Fadiga
what is economics
Mohamed Reply
what is the basic economic problem
John Reply
rules
Buayadarat_Gaming
unlimited wants vs limited resources
Nathan
what economics is all about?
Nomuhle Reply
what is a new paradigm shift
Austen Reply
Paradigm shift it is the reconcilliation of fedural goods in production
Shyline
fedural? what is that?
Aziz
factors that affecting economic system
Bemen Reply
crux
Shyline
what is meant by broadening the tax base?
Fiona Reply
Difference between extinct and extici spicies
Amanpreet 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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