topic 2 (fractions)-y4 09.ppt

8/14/2019 Topic 2 (Fractions)-Y4 09.ppt

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Murugiah Velayutham/TCG 1

Teaching of Mathematicsfor Year 4 Primary School

TOPIC 2 FRACTIONS


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FRACTIONS

Why is the study of Fractionsadifficult topic for young children?

Difficulty faced by students:

(1) Recognizing two equal fractions3/5 = 9/15

(2) Putting fractions in order by size2/3, 5/9, 7/12

(3) Symbol of a fraction represents a

single number 2 = 2/1= 4/2 = 8/4


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Meanings of Fractions

Interpretations:(1) Fractions as parts of unit whole(2) Fractions as parts of collection of

objects(3) Fractions as division of wholenumbers

It is very important to provideopportunities for students todifferentiate these interpretations


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(1) Fractions as Partsof a Unit Whole:

A fraction is a share of something .A fraction is also known as parts of unit one.

1 out of 2 equal parts 1 out of 4 equal partsOne halfis shaded One quarteris shaded


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(2) Fractions as Parts of aCollection of Objects

The number of objects required isobtained by first dividing the collection ofobjects into equal parts as stated in thedenominator and then multiply it with the

number in the numerator

two thirdof the objects are shaded


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Idea of Fractions

Proper Fractions:Fractions with the value of thenumerator less than the value of thedenominator.

Examples:

456

123,

45

23,

8

7,

5

2


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Idea of Fractions

Improper Fractions:Fractions with the value of thenumerator more than the value of thedenominator.

Examples:

62

62,

45

123,

8

74,

5

12


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Idea of fraction

Equivalent Fractions Two fractions of different numeratorand denominator with the same value.

1/2 = 4/8 3/6 = 7/14 One half is equivalent to four eighths

Three sixths is equivalent sevenfourteenths


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Idea of Fractions

Compound Fractions:Sometimes called mixed numbers.

Improper fractions can be written asmixed numbers

Examples:

How do we change improper fractions to

mixed numbers?How do we change mixed numbers to

improper fractions?

,8

31

8

11,

5

22

5

12

C i & A i


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Comparing & ArrangingFractions

Comparing Fractions:(1) When the denominators are equal, the

fraction with the bigger numerator isbigger.

Examples:

10

3

10

7thanbigger


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Comparing Fractions:(2) When the denominators are not equal,

then we should use equivalent fraction.

Examples: 3

2

5

3and

15

9

35

33

5

3

15

10

53

52

3

2

15

9

15

10thanbigger


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Arranging Fractions:(1) Ascending Order:

Smaller fraction bigger fraction

Example:

(2) Descending Order:

Bigger fraction smaller fraction

Example:

10

6

,10

5

,10

4

,10

3

,10

2

10

2,

10

3,

10

4,

10

5,

10

6


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Adding & Subtracting ofFractions

(1) Adding & Subtracting fractions with thesame denominators:

Example:

c

ba

c

b

c

a

4

3

28

26

8

6

8

15

8

1

8

5


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(2) Adding & Subtracting fractions withdifferent denominators:

i. Change each fraction to an equivalentfraction with common denominators.

ii. Add or subtract the numerator only.iii. Reduce the fraction if possible.

Example:

12

5

12

4

12

9

26

22

34

33

6

2

4

3


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(3) Solving Problems Involving Fractions:i. Understand the problem thoroughly.

ii. Identify what information has been given.

iii. Identify what does the question asks for.iv. Identify what operations are needed.

v. Find the solution.

vi. Checking the answer


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Problem Solving in Fraction

Example:

A watermelon is cut into eight slices. Aminah ate threeslices and Halim ate two slices. How many slices are left?

What information is given? Watermelon is cut into eight slices.

Aminah ate three slices.

Halim ate two slices.

What does the question asks for? How many slices of watermelon are left?

What are the fractions involved? 8/8 , 3/8, 2/8

What operations are needed? Tinggal => hasil tolak

Selesaikan 8/8 3/8 - 2/8 = 3/8

Semak jawapan 3/8 + 2/8 + 3/8 = 8/8


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Problem Solving in Fractions

Example:

A primary school has a building which is four storey high. Each floor hasfive classes. Year 1 pupils occupy three classes on the ground level and

Year 2 pupils occupy two classes on the second floor. What fraction of the

classes are occupied by Year 1 and Year 2 pupils?

What information is given? Four storey building.

Each floor has five classes.Year 1 pupils occupy three classes at ground floor.

Year 2 pupils occupy two classes at second floor.

What does the question asksfor?

What fraction of the classes are occupied by Year1 and Year 2 pupils?

What are the fractionsinvolved? Year 1: 3/20Year 2 : 2/20

What operations are needed? and = Addition

Solve 3/20 + 2/20 = 5/20 = 1/4

Check the answer 5/20 2/20 = 3/20

topic 2 (fractions)-y4 09.ppt

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