Variables are used to store data in memory and are assigned values using the equal sign. Variable names must start with a letter or underscore, cannot start with a number, and can only contain alphanumeric characters and underscores. Variable names are case-sensitive. There are immutable data types like numbers, strings, and tuples whose values cannot be changed, and mutable types like lists, dictionaries, and sets that allow values to be changed.

1. keyword is a reserved word.they are used for
special purposes in Python programming
language.

2. Variables
Variables are used to store data, they take
memory space based on the type of value we
assigning to them. you just have write the
variable name on the lef side of = and thevalue
on the right side.
num = 100

3. The name of the variable must always start with either
a letter or an underscore (_). For example: _abc, xyz.
The name of the variable cannot start with a number.
For example: 4d
The name of the variable cannot have special
characters such as %, $, # etc, they can only have
alphanumeric characters and underscore (A to Z, a to
z, 0-9 or _ ).
Variable name is case sensitive in Python which means
num and NUM are two diferent variables in python.
Some Rules of variables:

4. Data Types
A data type defnes the type of data.
1.Immutable data types – Values cannot be
changed.
2. Mutable data types – Values can be changed

5. Immutable:
1. Numbers
2. String
3. Tuple
Mutable:
1. List
2. Dictionaries
3. Sets