If for some reason I want to preform the addition first I can either change the order or use parentheses
Now to create something useful. Say you have a website that is getting ten thousand visitors a month, and you want to know how many visitors a month you might see in a few months if you can maintain a certain average rate of growth each month. A function can be authored to do something like that, and then copied and pasted into the console. Once it is copied into the console it can be called with arguments passed to it that contain the starting traffic, average rate of growth, and the number of months that I want to project.
A good starting point would be to open a text editor and start out with something like this:
Then save the file as something like index.html in a folder on your computer somewhere. Then in your web browser press ctrl+o and navigate to the index.html file and open it up. In the address bar your should see file:\/\/ rather than the usual https:\/\/ and then a URI to the location of the html file.