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Python was written with mathematics in mind, so let’s examine a simple math program. Several important new concepts will be introduced.

First, it is important to document your code. This will help you remember why you wrote things a certain way, and it can help other people better understand your program. In Python, lines that begin with “#” are treated as comments. Python won’t do anything with code after the # on a single line.

# This is a comment.

Second, is the concept of the variable. Unlike states text, such as “Hello World”, variables can change. However, they don’t change by themselves. First, you have to assign them a variable. Then you can change them later. In the following program, “x” is variable.

# x is assigned a value
x = 1

Third, you can perform operations to change, combine or compare variables. In the program below, we use the “+” operator to combine the variable x with the constant 5.

# x is assigned a value
x = 3

# x and 5 are combined
y = x + 5.0

# Result is displayed
print('Y = ', y)

The above program assigns a value to x and then adds 5 to x. The result is displayed as y. When writing calculations in code, we often want the result to be a decimal. Writing the 5 as “5.0” will tell the program that we want a decimal calculation. Each language may handle this differently, but it is a good habit to get into the habit of adding the “.0” or else you will face many hours of grief in the future.

Activity

• Write and run the above program. Save it as MyMathProgram.py
• Try out initial values for x. Your final result should change for each different value of x.

Leveling Up

• Add your won comments to the above program.
• Create additional variables and calculations, and display multiple values in the same line of results.

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