Learn to group one task into a function, pass data into it with parameters, and return a useful result with `return` so your code becomes easier to reuse and explain.
A function avoids repeated logic and forces you to think of one task as one reusable unit.
If you calculate a total many times, it makes little sense to rewrite the same structure over and over.
A function lets you encapsulate that task, give it a useful name, and call it whenever you need it with different data.
At this stage you do not need advanced variations. You need to understand name, parameters, block, and return value.
`calculateTotal` is the name of the function. `price` and `shipping` are parameters: they stand for the data that comes in. `return total` sends the result back so the rest of the program can use it.
This introduces a very important idea: separating the logic of the calculation from the moment you use it.
Parameters let you reuse the same idea with different inputs.
Returning a value means handing the result of the function back to the rest of the program.
Without `return`, a function may still do something, but it does not hand back a reusable result in the same way.
With `return`, you can save the result in a variable, use it inside another expression, or show it in the console later.
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