Following is the 9th class computer notes unit 2 according to the Federal Board of Intermediate and Secondary Education (FBISE)

Unit 2: Computational Thinking & Algorithms

Give short answers to the following short response questions (SRQs).

1. What is the major difference between solving simple problems and complex problems?

The major difference between solving simple problems and complex problems lies in the level of difficulty and the number of steps required to reach a solution. For simple problems, the four steps are used to solve the problem. However, for complex problems, the six-step problem-solving process could be used.

2. Why do software designers prefer to use IPO charts?

IPO charts are to visually represent the IPO model. Software designers prefer to use IPO (Input-Process-Output) charts because they help visualize how data flows through a system. IPO charts are considered a handy tool that software designers use to solve problems.

3. Differentiate between Computational thinking and Logical thinking.

Computational thinking

Using computation to solve problems requires the ability to think in a certain way, which is often referred to as ‘computational thinking’.

Logical thinking

Logical thinking refers to analyzing a particular situation or problem using reason and accordingly reaching up to one or more decisions that are sensible.

4. Write four properties of Computational thinking.

Following are the four properties of Computational thinking.

Decomposition: Breaking down the larger problems into smaller/ manageable ones and working on them one by one

Abstraction: by removing the unnecessary details to the solution, so you could be able to identify essential information.

Pattern Recognition: Examine the problem for a pattern or similarities between previously solved problems.

Algorithm Design: This is the actual design of the solution. This involves creating a step-by-step plan for the problem solution.

5. What are the methods used to design a solution?

There are two methods that are used to design a solution:

Flowcharts: A flowchart is a diagrammatic representation of an algorithm. It describes what operations are required to solve a given problem.

Concept Maps: A concept map is a graphical tool that represents concepts and relationships between them. The concepts in these maps are represented as boxes or circles, which relate to lines or arrows.

6. Which Computational thinking technique breaks down the problem into smaller parts?

Decomposition: Breaking down the larger problems into smaller/ manageable ones and working on them one by one. These smaller problems are referred to as subproblems.

7. Identify three computing problems from other subjects that you are studying in your class.

Mathematics: Optimization problems, such as finding the minimum or maximum value of a function.

Biology: Computational biology involves analyzing biological data using computing methods.

Physics: Simulating complex physical systems is a common computing problem in physics.

8. Why do we need to think computationally?

We need to think computationally because it encourages us not only to reflect clearly on a problem we’re solving but also to define a repeatable solution for it. Computational thinking can be thought of as an extension of logical thinking.

9. The telephone numbers usually have 9 digits. Out of these 9, the first two digits represent the area code and are it remains constant within a given area. The last 7 digits represent the number, and it cannot begin with 0. How many different telephone numbers are possible with a given area code?

To calculate the number of different telephone numbers possible with a given area code, we need to consider the restrictions on each digit:

i. The first digit (area code) has no restrictions, so it can be any digit from 0 to 9.

ii. The second digit (area code) also has no restrictions, so it can also be any digit from 0 to 9.

iii. The third digit (the first digit of the number part) cannot be 0, so there are 9 options (1 to 9).

iv. The remaining six digits (the number part) can each be any digit from 0 to 9, so there are 10⁶ possible combinations.

Therefore, the total number of possible telephone numbers with a given area code is: 10×10×9×10⁶ = =900,000,000

10. From city A to city B, there are 4 different roads and from city B to city C there are 2 different roads. Draw a map of a given situation and identify how many possible routes are there that someone can follow to reach from city A to city C passing by city B.

Number of possible routes=4×2=8

So, there are 8 possible routes from City A to City C passing by City B.

Give Long answers to the following extended response questions (ERQs).

Q 1. Identify whether the given problems are Decision Problems, Counting Problems or Search Problems. Write your answer in front of each problem given below:

a. Does a given binary string have an even number of zeros?  Decision Problem

This problem involves determining whether a property holds true for a given input (binary string). In this case, it’s determining if the number of zeros in the string is even.

b. Flipping a coin results in Head or tails. I flip a coin 20 times, how many different sequences of heads and tails are possible?  Counting Problem

This problem involves counting the number of possible outcomes (sequences of heads and tails) for a given scenario (flipping a coin 20 times).

c. Does a certain Java program say “yes” to an empty input? Decision Problem

This problem involves determining whether a certain property holds true for a given input (empty input in this case), i.e., whether the program outputs “yes” for an empty input.

d. How many ways can the letters of the word TRIANGLE be arranged? Counting Problem

This problem involves counting the number of arrangements (permutations) of the letters in the word TRIANGLE.

e. N-queens problem: where the goal is to place eight queens on a chessboard such that no queen attacks any other. Search Problem:

This problem involves searching for a solution that satisfies certain constraints. It’s an example of a search problem where the solution space needs to be explored to find a valid arrangement.

Q 2. A student has to take one course in physics, one in science and one in mathematics. He may choose one of 3 physics courses (P1, P2, P3), one of 2 science courses (S1, S2) and one of 2 mathematics courses (M1, M2). In how many ways can this student select the 3 courses he has to take?

To find the total number of ways the student can select the 3 courses, we multiply the number of options for each subject:

• Number of physics courses to choose from = 3 (P1, P2, P3)
• Number of science courses to choose from = 2 (S1, S2)
• Number of mathematics courses to choose from = 2 (M1, M2)

So, the total number of ways to select the courses is:

3×2×2=12

Therefore, the student can select the 3 courses in 12 different ways.

Q 3. Create an IPO chart which will accept the ages of four boys and calculate their total age and average age. The program must display both the total age and the average age.

4. Create an IPO chart of a scenario that allows a user to enter two numbers. The operation to be performed is either addition, subtraction, multiplication or division and accordingly the output should be given to the user.

Q 5. The child wants to plan a birthday party for their friend. a) Draw an IPO chart of this situation. b) Write down properties of computation thinking.

a) IPO Chart for Planning a Birthday Party:

b) Properties of computation thinking

The following are the properties of computation thinking:

Decomposition: Breaking down the larger task of planning a birthday party into smaller, more manageable parts and working on them one by one such as selecting a theme, choosing a location, planning activities, arranging food, and managing invitations. These smaller problems are referred as sub-problems. This way we simplify the problem and solve it easily.

Abstraction: Focusing on the essential aspects of the birthday party planning process while ignoring irrelevant details, such as specific decoration designs or individual guest preferences.

Pattern Recognition: Identifying common elements or patterns in birthday party planning, such as typical activities, popular themes, or preferred foods, to make informed decisions.

Algorithm Design: This involves creating step-by-step procedures or plans to organize the birthday party efficiently, ensuring that all necessary tasks are completed in the right order to achieve the desired outcome.

Select the suitable answer for the following Multiple choice questions.

1. For a problem, we face in real-world situations. In what sequence do we follow the steps?

I. make some solution.

II. understand the real-world problem.

III. Instruct the computer to behave accordingly.

a) I, II, III              

b) I, III, II

c) II, I, III

d) II, III, I

2. The following are types of computing problems

I. Counting Problems

II. Search Problems

III. Decision Problem

a) l and II

b) l and III

c) ll and III

d) l and II and III

3. Computational thinking is

a) Programming

b) Thinking like a computer

c) Coding

d) Logically solving problems

4. To solve Search problems, we need to

a) Provide the moves.

b) Provide start state.

c) Provide the end state.

d) a,b and c

5. The eight queens puzzle is the problem of

a. Sorting

b. Searching

c. Counting

d. Both a and b

6. Finding the location of the element with a given value is

a) Search

b) Traversal

c) Sort

d) None of the above

7. In IPO Charts, we have

a) Input, Plan, Output

b) Input, Program, Output

c) Input, Process, Output

d) Input, Proceed, Output