Mathematica handle's variables in a subtly different way to the way we handle them in ordinary written mathematics. Let's go over the details:
Mathematica variables can have multiple letters in their names, and even numbers (except numbers are not allowed in the first position.) e.g. valid variable names are x, or pressure, or even side23. A variable name like 5short would not be allowed, however, and in fact this would be interpreted by Mathematica as 5*short.
Variable names beginning with a capital letter should not be implemented by the user in Mathematica. The reason for this is that Mathematica's own built-in commands and variables all begin with capital letters. Using lower-case when creating your own variables guarantees that you'll experience no conflicts with built-in commands. Having said that, Mathematica will not actaully complain even if you do use a capitalized user-variable.
Pay careful attention as you complete these exercises to the differences between delayed and immediate assignment when assigning values to variables.
Remember, as we said in the introduction to the last notebook, in order to tell Mathematica that you want it to actually evaluate what you have typed, hit the ENTER key over on the extreme right side of your keyboard on the numeric keypad. Again, don't confuse this with the RETURN key, which merely starts a new line of text.
You can now switch to the actual Mathematica practice notebook by
clicking on the button at left. It will take a while to start up! Don't forget to come back
here when you're done by using the Applications menu! (You can also use this
menu just to come back here to reread the instructions.) See you in a few
minutes.
Welcome back! Hopefully everything went well. You're now finishing learning about Variables in Mathematica. You may now go to the Table of Contents for the Mathematica Basics Labs, or simply quit.