Format text and add mathematical notation in questions

You can format text or add mathematical notation in a question's Prompt and Answer/Explanation, as follows:

Use Markdown, which enables you to add simple formatting easily. For example, you can put text in italics by surrounding the text _with underscores_.
Use HTML, which enables you to add any arbitrary formatting. HTML is more complex, but with HTML you can make your question look like just about anything.

Use LaTeX, which enables you to add mathematical expressions quickly.

For	Surround with	Example
Expressions that are inline with the text	dollar signs	$e^{i \pi} + 1 = 0$
Equations that are centered on their own line	double dollar signs	$$\int_0^1 x^2 = \frac 1 3$$
Visible dollar signs in the question	precede each dollar sign with a backslash (\$)	If red tulips cost \$2 each, while tulips cost \$1 each, and blue tulips cost \$3 each, how much does it cost to buy a shipment of 75 red tulips, 150 white tulips, and 75 blue tulips?

Note: MathType users can use "Copy with Plain TeX" to generate LaTeX code from your work.

((Question for later:

I don't know why, but I'm having trouble with question 100188, which I created. Do I need to share it for you to check it for me Brian? No rush, but at some point I'd like to understand it better.))