Scratch paper alternatives? How do you practice complicated calculation when the problem is displayed on your computer screen? Do you always have pieces of paper on the side, or do you have a Wacom tablet connected to your computer? Or are there any other convenient tools? Latex is not for quickly writing down equations, right?
 A: When you're a little unsure of a solution or calculation, its good to get all of your ideas out on scratch paper until you feel you've got something. When you do, it can be very useful to type things out again in Latex, because you are forced to review every step in your argument. In doing this I tend to find errors which I passed over while writing it on paper, which can save you a lot of points if it is a homework assignment you are turning in. 
While it might seem arduous to type out long calculations in Latex, this is not the case if you use the great advantages that latex has over pen and paper.
(1) You cannot copy and paste with a pen and paper. The majority of the time when doing lengthy calculations where you want to show all your work, you're only changing minor things in each line, and it can save you a great deal of time to just copypaste the previous line and make the minor changes that are necessary for the next line instead of writing up every single line by hand.
(2) If you write a certain symbol very frequently, you can enter in a new command in the preamble which enables you to type the same symbol in a shorter amount of keystrokes. For example, in my analysis class I use the \mathbb{R} and \mathbb{N} a lot, and typing this out again and again can add up to a lot of time. Fortunately, I can add in \newcommand{\N}{\mathbb{N}} to the preamble, and now all I need to do to get the symbol for the natural numbers is just type \N!
(3) Your handwriting is legible. Nobody wants to read through your homework/ideas if it looks like you tried to write them while in the middle of an earthquake.
I'm sure there are plenty of other benefits I might have forgotten, or are known to people who are better with Latex than I am (in which case feel free to edit them in), but I hope this gives you a better idea of a different avenue you can take while working with lengthy calculations :)
