COMPUTINGStd IX

Ex 10.1 page 116

Q1. Write any four field where computers is being used

Uses of ComputerText book PAGE No. 111

• Reservations in railways & airplanes.

• Computerized bills of electricity, telephone, insurance premium.

• Workers paybills

Uses of ComputerText book PAGE No. 111

• Merit list & Results of various organization.

• Printing of news paper and magazines..

• Widely used in Banks, Share market & Insurance Company.

Uses of ComputerText book PAGE No. 111

• Scientific research.

• Launching of satellite.

• Forecasting of weather.

• Television & cable advertisement etc.

Why do we need computers ? Text book PAGE No. 111 / 112

• Have more and more knowledge,

• Generate new knowledge.

• Utilize the existing knowledge in best possible way and more efficiently.

Ours is a knowledge oriented society and we are eager to

Devices used for calculation Text book PAGE No. 112

• Abacus

• Logarithms

• Slide rule

• Pascal’s adding machine

• Babbages analytical Engine

• Turing machine

• Calculator

Abacus

Abacus

Abacus, instrument used in performing arithmetic calculations. Many early civilizations used the abacus. In ancient Roman culture it was a sand-covered wax tablet, marked table, or grooved table or tablet. A simplified form of abacus was used in medieval England. The abacus is still used in China and Japan.

Logarithms

The first tables of logarithms were published independently by the Scottish mathematician John Napier in 1614 and the Swiss mathematician Justus Byrgius in 1620. The first table of common logarithms was compiled by the English mathematician Henry Briggs.

SLIDE RULE

SLIDE RULE

Slide RulePrior to the Invention of the hand-held calculator, the slide

rule was a standard tool for engineers and scientists. Operating on the principle that all mathematical computations may be carried out on sets of sliding scales, the device looks much like a heavily calibrated ruler with a movable midsection. The midsection, called the sliding center scales, is engraved with fine lines to allow the user to align different logarithmic scales rapidly and efficiently. Multiplication, addition, subtraction, division, squaring, cubing, extracting roots, and more complicated calculations were computed regularly by adept users until well into the 1960s.

Pascal Adding Machine

Pascal Adding Machine

Pascal (computer), a concise procedural computer programming language, designed 1967-71 by Niklaus Wirth. Pascal, a compiled, structured language, built upon ALGOL, simplifies syntax while adding data types and structures such as subranges, enumerated data types, files, records, and sets. Acceptance and use of Pascal exploded with Borland International's introduction in 1984 of Turbo Pascal, a high-speed, low-cost Pascal compiler for MS-DOS systems that has sold over a million copies in its various versions.

Babbages analytical Engine

Babbages analytical Engine

Analytical Engine, a mechanical calculating machine that was conceived by British mathematician and scientist Charles Babbage in 1833 but only a part of which was ever constructed. The first general-purpose digital computer, the Analytical Engine, although conceived long before electronics technology appeared, was to have been capable of storing instructions, performing mathematical operations, and using punched cards as a form of permanent memory.

.

Turing Machine

In 1936 British mathematician Alan Turing proposed the idea

of a machine that could process equations without human direction. The machine (now

known as a Turing machine) resembled an automatic typewriter that used symbols for math and logic instead of letters. Turing intended the device to be used as a “universal machine” that could be programmed to duplicate the function of any other existing machine. Turing’s machine was the theoretical precursor to the modern digital computer.

Calculator

In 1967 a team of three engineers from Texas Instruments, Inc. invented the portable,

electronic, handheld calculator. Jack Kilby, widely known as the inventor of the integrated circuit (IC), or computer

chip,along with Jerry Merryman and James Van Tassel, built an IC-based, battery-powered miniature calculator that could add, subtract, multiply, and divide. This basic calculator could accept 6-digit numbers and display results as large as 12 digits. The prototype of this device is now displayed in the Smithsonian Institution, based in Washington, D.C.

Parts of a computer Text book PAGE No. 113

• Input Devices

• Output Devices

• Arithmetic Logical Unit (ALU)

• Memory Unit

• Control Unit

Input Devices

• Input Devices: - It is used to pass on the data and program to the computer.

Parts of a computer Text book PAGE No. 113

Input Devices

CPU

• Central Processing Unit: -A unit consisting of ALU, Memory Unit and Control Unit is called CPU.

Parts of a computer Text book PAGE No. 113

• Output Devices: - It is used to pass on the final answer to the user.

Output Devices

Input Devices

CPU

Parts of a computer Text book PAGE No. 113

Output Devices

ALU

Input Devices

CPU

• Arithmetic Logic Unit: - It is a part which does the calculation work apart from some other work.

Parts of a computer Text book PAGE No. 113

Output Devices

ALU

Control Unit

Input Devices

CPU

• Control Unit: -This unit controls all other units. It also give instruction to other units as and when required by a program.

Parts of a computer Text book PAGE No. 114

Output Devices

ALU

Control Unit

Memory Unit

Input Devices

CPU

• Memory Unit: - The data and instruction, which we supply through input devices, are stored in a unit called “memory unit”. This data can be used whenever required.

Parts of a computer Text book PAGE No. 113

Ex 10.1 page 116

Q1. What are the special features of a computer?

Some features of computer Text book PAGE No. 114

• A computer carries out the instruction most obediently and very accurately.

• It works continuously for lengthy or repetitive type of work.

• It works with a tremendous speed.• It has a memory with voluminous data and / or

large number of instruction can be stored.• The information stored in the computer can be

processed and various reports can be generated.

• Numeric Computation• Alphabetic Computation• Alpha-numeric computation

Types of ComputationText book PAGE No. 114

Text book PAGE No. 116

Q3 ) Give an example of alpha-numeric computation.Ans ) To prepare a list of the ages of the students of your class as on today and arrange their ages in the descending order.

Write down various stages of computation in the following example

₪ 27 - 13 ( 64 ÷ 2 – 19 x 13 ) -11

═ 27 - 13 ( 32 – 19 x 13 ) -11

═ 27 - 13 ( 32 – 247 ) -11

═ 27 - 13 ( - 215 ) -11

═ 27 + 2795 – 11

═ 2882 – 11

═ 2811

Q4) Write down various stages of computation in the following example

• 15 – ( 18 x 5 ) + ( 60 ÷12 ) – (– 20 ) + 2═ 15 – ( 18 x 5 ) + ( 5 ) – (– 20 ) + 2═ 15 – ( 90 ) + ( 5 ) – ( – 20 ) + 2═ 15 – ( 90 ) + ( 5 ) + 20 + 2═ – 75 + 5 + 20 + 2═ – 70 + 20 + 2═ – 50 + 2═ – 48

Q4) Write down various stages of computation in the following example

• 12 – ( +3 ) + 10 – ( 8 x 12 ) ÷ ( + 22 )

= 12 – ( +3 ) + 10 – ( 96 ) ÷ ( + 22 )

= 12 – ( +3 ) + 10 – 4.36

= 12 – 3 + 10 – 4.36

= 12 + 7 – 4.36

= 19 – 4.36

= 14.64

Way’s of representation Text book PAGE No. 125

• Algorithm: - The step by step procedure to solve a problem is known as an algorithm

Q1. What is an algorithm?

•Flowchart: - The diagrammatic representation of an algorithm is called a “Flowchart”.

Q2. What is a flowchart?

To solve the problem with the help of computer

• Analyse the problem.

• Think of a solution procedure.

• Write step by step instructions to get the solution.

• Draw a flowchart.

Flowchart

Terminal Box for “START” and “STOP”.

Terminal Box

START STOP

Examples

Flowchart

“PRINT” or “INPUT” or “OUTPUT” box.

Input & Output Box

Input the value of A

Print thevalue of A

Read the valueof A,B and C

Examples

Rectangular box for calculation and storage.

FlowchartRectangular Box

Calculate the value ofI = (P *N*R) / 100

Store the value of I

Examples

Flowchart

Decision box

Decision box

Yes No

Examples

Is a>b

Flowchart

Lines with arrows to indicate the direction of flow.

Flow Lines

Start

Read the value of A

Examples

Flowchart

Connectors to link the flowcharts

Connectors

Is A > 10No

Yes

Print thevalue of A

1

Examples

START

Read the value of ‘m’

Store thevalue of ‘m’

Print thevalue of ‘m’

STOP

START

Read the value of ‘m’

Print thevalue of ‘m’

STOP

START

Read the value of ‘m’

Store thevalue of ‘m’

Print thevalue of ‘x’

STOP

Read the value of ‘n’

Store thevalue of ‘n’

1

1

Calculatex = m + n

Store the valueof x

START

Read the value of ‘m’

Print thevalue of ‘x’

STOP

Read the value of ‘n’

Calculatex = m + n

Text book page 125Q5) Draw a flow chart to print the area and

perimeter of the rectangle.START

Read the value of length as ‘l ’

Print the value of Perimeter as P

STOP

Read the value of breadth as ‘b’

Calculate Perimeter asP = 2 ( l + b )

1

1

Calculate Area as A = l x b

Print the value of Area as A

Text book page 125Q6) Draw a flow chart to find the area of a

triangle whose base is b and height is h.

START

Read the value of base as ‘b ’

STOP

Read the value of height as ‘h’

Calculate Area as A = ½ x b x h

Print the value of Area as A

Text book page 125Q7) Draw a flow chart to find the average of

two given numbers

START

Read the value of ‘m’

Print the value of Average as ‘Av’ STOP

Read the value of ‘n’

Calculate Averageas ‘Av’ = (m + n) 2

Text book page 125Q8) Ram purchased one book for Rs. 40 and sold it for Rs. 45.

Draw a flow chart to print the profit made by Ram.

START

Read the value of C.P as C = Rs. 40

Print the value of Profit as ‘P’ STOP

Read the value of S.P. as S = Rs. 45

Calculate Profitas ‘P’ = S - P

Text book page 125Q9) The distance between the two towns is 100

Km. Draw a flowchart in meters and centimeters.START

Read the value of distance as ‘D ’= 100 km

Print the value of C = 1,00,00,000 cm

STOP

Calculate distance in centimeters as C = D x 1000 x 100

1

1

Calculate distance in meters as M = D x 1000

Print the value of M = 1,00,000 m

Text book page 125Q10) A plot size 50m X 60m is purchased at the rate of Rs.

1120/- per square meter. Draw a flowchart to print the cost of the plot.

START

Read the value of length as ‘l ’= 60m

STOP

Read the value of breadth as ‘b’= 50m

Calculate cost asC = ( l x b ) x r

1

1

Print the value of Cost as C

Read the value of Rate as ‘r’= Rs. 1120

Text book page 125Q12) The length and the breadth of a rectangle is input through keyboard. Draw a flowchart to print the area of the rectangle

only if the perimeter is greater than 30.START

Read the value of length as ‘l ’

STOP

Read the value of breadth as ‘b’

Calculate Perimeter asP = 2 ( l + b )

1

1

Calculate Area as A = l x b

Print the value of Area as A

IsP>30

Yes

No

START

Read the value of ‘a’

Read thevalue of ‘b’

Isa > b

YesNoPrint ‘The valueof a is greater’

Print ‘The valueof b is greater’

STOP

START

Read the value of ‘a’

Read thevalue of ‘b’

Isa > = b

Yes

No

Print ‘The valueof b is greater’

Isa = b

Print ‘The value of a = b’

Yes

No

Print ‘The valueof a is greater’

STOP

START

Read the value of a, b and c

Is a < b

Is a < c

Is b < c

Print thevalue of c

Print thevalue of b

Print thevalue of c

STOP

NoYes

Print thevalue of a

No

YesYes

No

Text book page 125Q11) Draw a flowchart to print the smallest of the three

distinct numbers.