# How to change / to be horizontal?

I like to change a/b to be

a
-
b


how to do that?

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yes,I only can use / now. – sam Jun 18 '11 at 13:34
See my answer below. But really, since you ask this very elementary question, I guess you do not have access to any form of documentation? You need to remedy that. LaTeX is too complex to use without documentation. – Harald Hanche-Olsen Jun 18 '11 at 13:36
Or have a look at this one: en.wikibooks.org/wiki/LaTeX – Harald Hanche-Olsen Jun 18 '11 at 13:42

\frac{a}{b}, in math mode of course.

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For fractions use $\frac{a}{b}$, like Harald Hanche-Olsen said. For inline-math I still like fractions that use / because a \frac is often too tall. Here is a definition for a nicer fraction that uses /:

\def\nicefrac#1#2{\leavevmode%
\raise.5ex\hbox{\small #1}%
\kern-.1em/\kern-.15em%
\lower.25ex\hbox{\small #2}}


It is used like this:

\nicefrac{a}{b}

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The nicefrac package, or the units package, also offer a \nicefrac command. – Gonzalo Medina Jun 18 '11 at 13:46
The xfrac package seems to be the better choice. – Thorsten Donig Jun 18 '11 at 13:51
Is this kind of command can be used on MathJaX? Because I can't try success on Statistical Analysis board. – sam Jun 18 '11 at 13:52
You can also use $\dfrac{a}{b}$ if you want a larger fraction in inline math mode. – Peter Grill Jun 18 '11 at 14:51
@Peter: using \dfrac in inline math is not very good because it changes the space between lines and by default LaTeX uses smaller fractions in inline math just to avoid this. – Spike Jun 18 '11 at 15:16