Form One - Decimals Form One

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 1/42

MATHEMATICSMATHEMATICS

FORM 1FORM 1

MATHEMATICSMATHEMATICS

FORM 1FORM 1

DECIMALSDECIMALS

Created By: Sepang District Group

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 2/42

Learning outcomes:

Represent fractions 1/10 and 1/100 as a

decimals and vice-versa

Represent fractions with denominators 10,100 1000 as decimals.

Read and write decimals to thousandths.

Change fractions to decimals and vice-versa

Decimals and Fractions

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 3/42

INTRODUCTION

4.123kg

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 4/42

RELATIONSHIP BETWEEN

DECIMALS AND FRACTIONS

101=

The part is one part out of ten parts

= 0.1

1 0

1.0

0.110

0 0

Represent fractions as decimals

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 5/42

RELATIONSHIP BETWEEN

DECIMALS AND FRACTIONS

100

13=

The part is thirteen parts out of one hundred parts

=

0.13

10 .0

13.0

00.13

1003 003 00

0 00

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 6/42

Represent fractions with denominators 10, 100,

1000.

Decimals

Fractions10

1

100

1

1000

1

0.1 0.0010.01

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 7/42

Read and write decimals up to

thousandths.

0 4 7.

Zero point sevenfour 

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 8/42

5 8.3

2

Three eightpoint five two

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 9/42

38.74Thirty-eight point seven four 

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 10/42

CHANGE FRACTIONS TO

DECIMALS

4

3 = 3 ÷ 475.0

00.34

2 80

2020

00= 0.75

RULE: Divide the numerator by the denominator.

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 11/42

TRY!

5

2= 0.4

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 12/42

CHANGE DECIMALS TO

FRACTIONS

RULE : Express the decimal as a fraction by using 10, 100,

1000 and so on, as the denominator of the fraction.

5

20.4

2

= =10

45

4 ÷ 2

10 ÷ 2

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 13/42

0.05 =20

1

TRY!

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 14/42

Place Value and Value of Each Digit in

Decimals

Learning Outcomes:

State the place value and value of each in decimals.

Compare the values of two given decimals.

Arrange decimals in order.

Round decimals to the nearest whole number up to three

decimal places.

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 15/42

PLACE VALUE AND VALUE OF

EACH DIGIT IN DECIMALS

.

Place value

Tens Units - Tenths Hundredths Thousandths

 value -

Decimalplace

4 5 . 8 6 2

40 5 0.8 0.06 0.002

1st  2nd 3rd

4 5 8 6 2

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 16/42

TRY!

81.654State the place value of the underlined digit 

State the value of the underlined digit 

Hundredths

0.05

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 17/42

 Arrange 2.5, 2.05, 2.53, and

2.505 in increasing order

2.5 =2.500

2.05 = 2.0502.53= 2.5302.505= 2.5050

2.05 2.5, ,2.505 ,2.53The decimals have arranged in

increasing order

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 18/42

Round off 14.78

to the nearest whole number

4 . 7 8

The first digit on the right is greater than 5

+1

 Add I to digit 4

1 5

Drop all the decimals

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 19/42

Round off 5.316 to 1 decimal place

5 . 3 1 6

Underline digit 3

(1st decimal place).

The first digit on the right 

is less than 5

Do not 

change digit 3

Drop all the digits

to the right 3

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 20/42

Round off 4.387 to 2 decimal places

4 . 3 8 7

Underline digit 8

(2nd

decimal place).

The first digit on the right 

is more than 5

 Add 1 to 8

9

+1

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 21/42

TRY!34.561

1) To the nearest whole number

2) To 1 decimal place

3) To 2 decimal places

3534.6

34.56

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 22/42

Addition and Subtractions of Decimals

Learning Outcomes:

Add decimals

Solve problems involving addition of decimals.

Subtract decimals.

Solve problems involving subtraction of decimals

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 23/42

 ADDITION OF DECIMALS

34.571 + 21.332 =

34 . 5 17

33.12 2+ 09.55 3

1

55.903

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 24/42

10.345+112.3+8.61=

12 . 3 00

16.8 0+ 52.13

1

131.255

1 .0 431

5

1

1 5

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 25/42

SUBTRACTION OF DECIMALS

64.718 - 21.404 =

64 . 7 8104.12 4-13.34 4

1

43.314

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 26/42

10.345 - 2.83 =

2 . 8 03-

15.7 5

13

7.515

1 .0 43 5

90

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 27/42

Multiplication and Division

of Decimals

Learning Outcomes:

Multiply two or more decimals

Solve problems involving multiplications of 

decimals

Divide

 A decimals by a whole Number 

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 28/42

Multiplying Two or More

Decimals

Mentally multiply decimals by 10

1.746 x 10 =1 7 4 6

Shift the decimal point one place to the right.

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 29/42

Mentally multiply decimals by 100

1.746 x 100 =1 7 4 6

Shift the decimal point two places to the right.

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 30/42

Mentally multiply decimals by 1000

1.746 x 1000 =1 7 4 6

Shift the decimal point three places to the right.

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 31/42

Mentally multiply decimals by 0.1

17.5 x 0.1 = 1 7 5

Shift the decimal point one place to the left.

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 32/42

Mentally multiply decimals by 0.01

17.5 x 0.01 1 7 5

Shift the decimal point two places to the left.

0=

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 33/42

Mentally multiply decimals by 0.001

17.5 x 0.001 1 7 5Shift the decimal point three places to the left.

= 00

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 34/42

8 4 2 x 7 =

8 4 2

x 7

5 8 9 4

two decimal places

two decimal places

5 8 9 4

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 35/42

1 9 x 3 =

1 1 9

x 5

55

9 5

one decimal place

one decimal place

1 5

3

3 75614

14 6 5

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 36/42

1 9 x 3 =

1 1 9

x5

55

9 5

one decimal place

one decimal place

1 5

3

3 7

5614

14 6 5

two decimal places

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 37/42

1 9 x 3 =

1 1 9

x

5

55

9 5

1 5

3

3 7

5614

14 6 5

one decimal place

one decimal place

three decimal places

0

0

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 38/42

Mentally divide decimals by 10

705.3 ÷ 10 7 0 5

Shift the decimal point one place to the left.

= 3

Dividing Decimals By 

 Whole Number

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 39/42

Mentally divide decimals by 100

705.3 ÷ 100 7 0 5Shift the decimal point two places to the left.

= 3

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 40/42

Mentally divide decimals by 1000

705.3 ÷ 1000 7 0 5

Shift the decimal point three places to the left.

= 30

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 41/42

35 ÷ 0.4

= 350.4

= 35 x 10

0.4 x 10= 350

4= 87.5

Multiply the numerator

 And denominator by 10

to change the denominatorto a whole number

8/3/2019 Form One - Decimals Form One

http://slidepdf.com/reader/full/form-one-decimals-form-one 42/42

9 ÷ 3.12

= 93.12

= 9 x 100

3.12 x 100= 900

312= 2.8846

Multiply the numerator

and denominator by 100

to change the denominatorto a whole number