Doing calculations

Besides writing math, sometimes it's useful to actually calculate something.

We have several options:

• The calc package offers basic math with LaTeX, with lengths and counters
• The fp package provides fixed point arithmetic with high precision
• The pgfmath package belongs to the PGF/TikZ package and provides many functions and a good parser
• LuaLaTeX is a version of LaTeX which allows programming calculation in the programming language Lua

Here, let's work with the pgfmath package, as we already worked with TikZ, and it's better documented than the other options.

How to do it...

Follow these steps:

1. Start a document, load the tikz package, and begin your document without indentation at the beginning:

   \documentclass{article}
   \usepackage{tikz}
   \begin{document}
   \noindent

2. In your text, use the \pgfmathparse command for calculating and the \pgfmathresult command for printing:

   In a right-angled triangle the two shortest sides
   got widths of 3 and 7, respectively. The longest side...