Class 9th    Chapter # 01     Problem Solving

• Flowcharts Definition:

• Examples of Flowcharts: 

    2. Flowchart represents how to find the volume of the cube.

    3. Flowchart to find the sum, product & average of 5 given numbers.

    4. Flowchart to find, whether the given number is odd or even:

 Class 9th     Chapter # 01

• Flowcharts Definition: It is a graphical representation of the steps to solve a problem.
• Importance of Flowcharts in Problem Solving: It is more effective to visualize a solution graphically than a text.
• It also makes it effective to verify whether a solution is correct or not.
• Determining Requirements for a Flowchart: 
• Inputs: It means taking data from the user.
• Processing: These steps are used for performing calculations & storing the results of calculations.
• Input ⇒ Process⇒ Output
• Decision Making: To determine whether a statement is true or false & taking appropriate steps accordingly.
• Outputs: These are used to display information & usually this information exhibits processed results.
• Flowchart Symbols: Flowcharts use special shapes to represent different types of actions or steps in a process.
• Symbol                       Name               Description

 Unit # 01    

Planning a solution:

Some strategies are.

1. Divide & conquer: It divides a complex problem into smaller problems.
2. Guess, check & improve: The designer guesses a solution to a problem & then checks the correctness of the solution.
3. Act it out: The designer defines the list of "to-do" tasks. Afterwards he/she performs a task.
4. Prototype (Draw): This technique draws a pictorial representation of the solution. It is not the final solution, however, it may help designer to understand the components of the solution.

• The selection of a strategy depends upon the nature of the problem.
• Candid Solutions:
• Candid⇾ Refers ⇾Unplanned
• Example: If you are asked to find number of students in your school who can play cricket.
• Candid Solution: 

You can estimate by finding cricket players in your class & then multiplying it by the total number of classes in your school.

(Cricket players in your class) X (Total numbers of classes in school)

• For exact solutions: You have to visit each class or getting data from teachers.
•  Selecting the Best Solution: 
• Example: Assume that names of all the students in your school are available on a website & you are asked to search a name.
• Possible Solutions:

1. Look at each name on the website one by one until the name is found or list is over.
2. Take printouts & search required name.
3. Copy names, put them in Excel sheet & sort them in alphabetical order.
4. Press Ctrl+F, when the list is in a browser. You can type the name to search automatically.

 Class 9th    Chapter#01     Problem Solving

Defining a Problem: Strategies to define the problem. (For complex problems)

i. Gain Background Knowledge: we try to know the situation & circumstances in which the problem is happening. 

ii. Use Guesses: we try to guess the unknown information through guess. These guesses may be bases upon past experiences.

iii. Draw a Picture: we can draw a picture & fill the information.

Understanding a Problem.

Understand problem before solution:

A clear understanding of a problem makes it easier to solve and helps to save money, time and resources.

Understanding of Problem includes identification of 5 Ws:

what, who, when, where, why.

Example.

"Suppose your class teacher assigns you a task to prepare a list of students in your school whose names start with letter 'A'. The list is required in order to prepare an alphabetical directory of all school students & there is only one week to complete the task."

Identify 5 Ws; (to remember w's recall the word toy)

>What: to prepare a list of students. Names start with letter 'A'.

> Who: Students.

>Why: to prepare alphabetical directory of students.

>When: within one week.

>Where: School.