Miktex: What is the code for combinations? (a pair of parenthesis with one number on top of another)?

Answer 1

You don't need to specify MiKTeX; it's an implementation of LaTeX, and LaTeX is pretty much LaTeX. There are two easy ways to do this:

{5 \choose 3}

or

\binom{5}{3}

If you want something like this but not quite, look up the \genfrac command.

Answer 2

It's called a combinatorial: http://en.wikipedia.org/wiki/Combinatorial

Answer 3

/...\
| 5 |
| 3 |
\ .. /

We pronounce this as 5 over 3