# Help:Math

To use mathematical typesetting, begin mathematical expressions with $and end with$.

Superscripts (exponents) and subscripts are indicated just using the caret (shift 6, ^) or underscore, followed by the super/subscript. Curly-braces {} indicate "scope," so if one needs more than a single character (e.g., for a two-digit number or an expression as exponent or subscript), use {}. Most other mathematical symbols all begin with the "backslash" character (\) and most have relatively memorable names, like \frac \times \div \sum \geq \leq .

## Examples

To get $4 \times \frac {11} {12} = \frac {44} {12} = 3 \frac 8 {12} = 3 \frac 2 3$, type
$4 \times \frac {11} {12} = \frac {44} {12} = 3 \frac 8 {12} = 3 \frac 2 3$
To get $12 \div 4 > 2.5 \geq x$, type
$12 \div 4 > 2.5 \geq x$
To get $\overline{AB} \perp \overline{CD}$, type
$\overline{AB} \perp \overline{CD}$
Note the use of {} to surround AB.
To get f(x) = ax2 + bx + c, type
$f(x)=a x^2 + b x + c$
Note that the coefficient is followed by a space.

## Leaving extra space between lines containing mathematical expressions

Mathematical expressions usually use a different font and size from the normal font of your browser. Sometimes extra lines between expressions are important for clarity. In the following examples, note the use of "breakline" (<br>) followed by space and another <br> to leave an extra line between expressions.

Wiki markup


$\sum_{k=1}^{n}{k} = \frac {n(n+1)} 2$
Note the use of {} to show that n(n+1) is ''all'' in the numerator. <br>  <br>

$\int_{\theta=0}^{\pi}{\sin \theta}$
All Greek letters are just named. Note use of underscore.


What it looks like in your browser

$\sum_{k=1}^{n}{k} = \frac {n(n+1)} 2$ Note the use of {} to show that n(n+1) is all in the numerator.

$\int_{\theta=0}^{\pi}{\sin \theta}$ All Greek letters are just named. Note use of underscore.

## A more elaborate example

The following example -- mathematically utterly meaningless -- shows how to create annotated computations. The typesetting (not content) is borrowed from Wikipedia's nice article on casting out nines.

 $\mathit{12345}\,$ $\Rightarrow$ $0(x)\,$ A five digit number, an arrow, and some notations.‡ $\underline{-3\mathit{124}}\,$ $\Rightarrow$ $\times 2\,$ More stuff.** $\mathit{9} 2 \mathit{21}\,$ $\bigg\Downarrow$ We need two rows of arrow on one side. $\Downarrow$ But only one row of arrow on the other. ${2}\,$ $\Leftrightarrow$ $2\,$ Final comment.††

This line has no meaning.
** This line has even less meaning.
†† And so the conclusion cannot mean much!