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3                                                VARIABLES USING


                                                                               BLOCK CODING








                         Learning Outcomes

                      Introduction                                        What is Python?
                      What are Variables?                                 Naming Variables

                      Data Types                                          Performing Operations on Variables
                      Addition Operation using Block Coding



                 INTRODUCTION
                 In  the previous  chapters, you  have learnt the  basics of  algorithms, flowchart  and
                 pseudocodes. In this chapter, you are going to learn about another important component
                 of a program, variables. Variables are essential for storing and  manipulating  data in  a
                 program. Understanding how to use variables effectively will help you write more efficient
                 and dynamic code.

                 WHAT IS PYTHON?
                 Python is a high  level object-oriented  programming language.  It is a general purpose
                 language with interactive features. Python is an open source software and is founded by
                 Guido Van Rossum in 1991. Python is extensively used in:
                   Web Development                     GUI Application Development                Data Analysis
                   Software Development                Scientific Applications


                 WHAT ARE VARIABLES?
                 Variable is a name given to a location in the memory, to store values or
                 data. For example, you must have seen your mother naming boxes in the
                 kitchen. That box has a little storage capacity and your mother gave it a
                 name such as, salt, sugar, tea, etc.                                                   SUGAR   SALT

                 Variables are also similar to  a box  or a packet. These  packets  can  be
                 named, referenced and used to perform various mathematical operations.

                 So, a variable has a name (to refer to it), a type (kind of data it store and its size)
                 and a value (data). Usually variables are used to hold one or more values, result of
                 calculations, etc.

                 Scope of a variable
                 While creating a variable, you should also remember the limits of its usage. For example,
                 the  boxes  that  your  mother named, can be  used  in  the  kitchen  and  rarely outside  the
                 kitchen. Similarly, a variable can also be used in specific areas of a code, known as scope of
                 a variable.


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