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Mathematics

Decimal fractions

Educator section

Memorandum

13.4

a) 2 60 100 size 12{ { { size 8{"60"} } over { size 8{"100"} } } } {} 2,60
b) 13 625 1000 size 12{ { { size 8{"625"} } over { size 8{"1000"} } } } {} 13,625
c) 17 75 100 size 12{ { { size 8{"75"} } over { size 8{"100"} } } } {} 17,75
d) 23 875 1000 size 12{ { { size 8{"875"} } over { size 8{"1000"} } } } {} 23,875
e) 36 8 10 size 12{ { { size 8{8} } over { size 8{"10"} } } } {} 36,8

13.5 a) 0,83

  1. 0,2857142
  2. 0,8125
  3. 0,4

13.6

9 2 size 12{ { { size 8{9} } over { size 8{2} } } } {} 11 2 size 12{ { { size 8{"11"} } over { size 8{2} } } } {} 325 100 size 12{ { { size 8{"325"} } over { size 8{"100"} } } } {} 43 5 size 12{ { { size 8{"43"} } over { size 8{5} } } } {} 201 8 size 12{ { { size 8{"201"} } over { size 8{8} } } } {} 4056 1000 size 12{ { { size 8{"4056"} } over { size 8{"1000"} } } } {} 199 5 size 12{ { { size 8{"199"} } over { size 8{5} } } } {}
4 1 2 size 12{ { { size 8{1} } over { size 8{2} } } } {} 5 1 2 size 12{ { { size 8{1} } over { size 8{2} } } } {} 3 25 100 size 12{ { { size 8{"25"} } over { size 8{"100"} } } } {} 8 3 5 size 12{ { { size 8{3} } over { size 8{5} } } } {} 25 1 8 size 12{ { { size 8{1} } over { size 8{8} } } } {} 4 56 1000 size 12{ { { size 8{"56"} } over { size 8{"1000"} } } } {} 39 4 5 size 12{ { { size 8{4} } over { size 8{5} } } } {}
4,5 5,5 3,25 8,6 25,125 4,056 39,8

14. a) 0,3

  1. 0,6
  2. 0,23

Leaner section

Content

Activity: more revision [lo 1.4.2, lo 1.10, lo 2.3.1, lo 2.3.3]

We can convert proper fractions to decimal fractions in this way:

13.2 Did you know?

We can also calculate it in this way:

13.3 Which of the methods shown above do you choose?

Why?

13.4 Complete the following tables:

13.5 Use the division method as shown in 13.2 and write the following fractions as decimal fractions:

a) 5 6 size 12{ { {5} over {6} } } {} ........................................................................... ...........................................................................

...........................................................................

b) 2 7 size 12{ { {2} over {7} } } {} ........................................................................... ...........................................................................

...........................................................................

c) 13 16 size 12{ { {"13"} over {"16"} } } {} ........................................................................... ...........................................................................

...........................................................................

d) 4 9 size 12{ { {4} over {9} } } {} ........................................................................... ...........................................................................

...........................................................................

13.6 Can you complete the following table??

Improper fraction 9 2 size 12{ { { size 8{9} } over { size 8{2} } } } {} 45 5 size 12{ { { size 8{"45"} } over { size 8{5} } } } {}
Mixed Number 5 1 2 size 12{5 { { size 8{1} } over { size 8{2} } } } {} 25 1 8 size 12{"25" { { size 8{1} } over { size 8{8} } } } {} 39 4 5 size 12{"39" { { size 8{4} } over { size 8{5} } } } {}
Decimal fraction 3,25 4,056

14. BRAIN-TEASERS!

Write the following fractions as decimal fractions. Try to do these sums first without a calculator!

a) 1 3 size 12{ { {1} over {3} } } {} ........................................................................... ...........................................................................

...........................................................................

b) 2 3 size 12{ { {2} over {3} } } {} ........................................................................... ...........................................................................

...........................................................................

c) 23 99 size 12{ { {"23"} over {"99"} } } {} ........................................................................... ...........................................................................

...........................................................................

15. Do you still remember?

We call 0,666666666 . . . a recurring decimal . We write it as 0, 6 size 12{0, {6} cSup { size 8{ cdot } } } {} .

0,454545 . . . is also a recurring decimal and we write it as 0, 4 5 size 12{0, {4} cSup { size 8{ cdot } } {5} cSup { size 8{ cdot } } } {} .

We normally round off these recurring decimals to the first or second decimal place, e.g.: 0, 6 size 12{0, {6} cSup { size 8{ cdot } } } {} becomes 0,7 or 0,67 and 0, 4 5 size 12{0, {4} cSup { size 8{ cdot } } {5} cSup { size 8{ cdot } } } {} becomes 0,5 or 0,45

16. Time for self-assessment

  • Tick the applicable block:
YES NO
I can:
Compare decimal fractions with each other and put them in the correct sequence.
Fill in the correct relationship signs.
Round off decimal fractions correctly to:
  • the nearest whole number
  • one decimal place
  • two decimal places
  • three decimal places
Convert fractions and improper fractions correctly to decimal fractions.
Explain what a recurring decimal is.

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 1.10: We know this when the learner uses a range of strategies to check solutions and judges the reasonableness of solutions.

Learning Outcome 2: The learner will be able to recognise, describe and represent patterns and relationships, as well as to solve problems using algebraic language and skills.

Assessment Standard 2.3: We know this when the learner represents and uses relationships between variables in a variety of ways using:

2.3.1 verbal descriptions;

2.3.3 tables.

Questions & Answers

Ayele, K., 2003. Introductory Economics, 3rd ed., Addis Ababa.
Widad Reply
can you send the book attached ?
Ariel
?
Ariel
What is economics
Widad Reply
the study of how humans make choices under conditions of scarcity
AI-Robot
U(x,y) = (x×y)1/2 find mu of x for y
Desalegn Reply
U(x,y) = (x×y)1/2 find mu of x for y
Desalegn
what is ecnomics
Jan Reply
this is the study of how the society manages it's scarce resources
Belonwu
what is macroeconomic
John Reply
macroeconomic is the branch of economics which studies actions, scale, activities and behaviour of the aggregate economy as a whole.
husaini
etc
husaini
difference between firm and industry
husaini Reply
what's the difference between a firm and an industry
Abdul
firm is the unit which transform inputs to output where as industry contain combination of firms with similar production 😅😅
Abdulraufu
Suppose the demand function that a firm faces shifted from Qd  120 3P to Qd  90  3P and the supply function has shifted from QS  20  2P to QS 10  2P . a) Find the effect of this change on price and quantity. b) Which of the changes in demand and supply is higher?
Toofiq Reply
explain standard reason why economic is a science
innocent Reply
factors influencing supply
Petrus Reply
what is economic.
Milan Reply
scares means__________________ends resources. unlimited
Jan
economics is a science that studies human behaviour as a relationship b/w ends and scares means which have alternative uses
Jan
calculate the profit maximizing for demand and supply
Zarshad Reply
Why qualify 28 supplies
Milan
what are explicit costs
Nomsa Reply
out-of-pocket costs for a firm, for example, payments for wages and salaries, rent, or materials
AI-Robot
concepts of supply in microeconomics
David Reply
economic overview notes
Amahle Reply
identify a demand and a supply curve
Salome Reply
i don't know
Parul
there's a difference
Aryan
Demand curve shows that how supply and others conditions affect on demand of a particular thing and what percent demand increase whith increase of supply of goods
Israr
Hi Sir please how do u calculate Cross elastic demand and income elastic demand?
Abari
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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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