comments are useful for explaining the thought process in programs it is possible to combine the strengths of the two programs above and have both compact variable names and more detailed description of what each variable means this can be done using commentsas illustrated in the following exampleprogram for computing the growth of money deposited in bank primary initial amount interest rate in the number of years amount primary ( + / )** print(amountin this codeall the text following the symbol is treated as comment and effectively ignored by python comments are used to explain what the computer instructions meanwhat the variables representand how the programmer reasoned when writing the program they can be very useful for increasing readabilitybut they should not be over-used comments that say no more than the codefor instancea set to are not very useful all variables have types so far all the variables we have used have been numberswhich is also how we are used to thinking of variables in mathematics howeverin computer program we can have many different kinds of variablesnot just numbers more preciselya variable is name for python objectand all objects have type the type of variable python is usually decided automatically based on the value we assign to it for instancethe statement will create variable of the type integeror intwhereas will create variable with type floatrepresenting floating point number we can also have text variablescalled stringswhich have type str for instancethe helloworldexample above could have been written as hello "helloworld!print(hellohere we create variable hellowhich automatically gets type strand then print the contents of this variable to the screen the output is exactly the same as for the first example of we can check the type of variable using the built-in function typeprint(type(hello)print(type( )print(type(primary)print(type( )