My girlfriend asked for LaTeX cheatsheets. There are many of them online, but she was specifically looking for notational commands for algebra and number theory. You need to be aware that notation is very specific for your teacher. So standardization has not been successful to raise mathematical symbols from a representational to a semantical level. In US/UK/AU (in my experience), there is little information encoded in notation and information is provided in short, concise sentences. In Europe, this is different and every teacher has his/her own notation.
But let’s get back to the point: I recommend the following cheatsheets, but evaluate yourself whether it fits your field.
-
LaTeX 2ε Cheat Sheet
[only page 1 is recommendable, citations are outdated] (by Winston Chang) - Theoretical Computer Science Cheat Sheet (by Martin Jansche)
- LaTeX Mathematical Symbols
- The Comprehensive LaTeX Symbols List (by Scott Pakin/TUG)
- Short Math Guide for LaTeX (by Michael Downes/AMS)
- A quick guide to LaTeX (by Dave Richeson)
If you need a more comprehensive reference, the LaTeX wikibook is a nice start. For a german audience, LaTeX@TUGraz also does a good job IMHO.
And as always: If you look for a symbol and have internet connection, detexify makes your life much easier!