You can copy mathematical expressions from wikipedia using cntrl+c and paste them into latex. You will get proper latex code. The title is pretty self-explanatory, useful if you see a nice definition or matrix you want to use in a text.

There are three methods for displaying formulas in Wikipedia: raw HTML, HTML with math templates (abbreviated here as {{math}}), and a subset of LaTeX implemented with the HTML markup $$ (referred to as LaTeX in this article).

The study of mathematics as a "demonstrative discipline" began in the 6th century BC with the Pythagoreans, who coined the term "mathematics" from the ancient Greek μάθημα (mathema), meaning "subject of instruction".

Equations are centered on the page and labeled with Arabic numerals, right-aligned, in parentheses, and referred to only by those numbers in the text – e.g., you should always say “as seen in (3)” rather than “as seen in Equation (3)”.

Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes.

Equations should be numbered consecutively beginning with (1) to the end of the paper, including any appendices. The number should be enclosed in parentheses and set flush right in the column on the same line as the equation. It is this number that should be used when referring to equations within the text.

First, an equation is a way to say that one thing is equal to, or the same value as, another. A formula is a special equation that expresses an important relationship between variables expressing commonly-used ideas, like speed, temperature, etc.