# TeX Math
Inline math goes between `$` characters, and display math
goes between `$$`:
```````````````````````````````` example
Let $x$ and $y$ be integers such that
$$x=y + 2$$
.
<p>Let <span class="math inline">\(x\)</span> and <span class="math inline">\(y\)</span> be integers such that
<span class="math display">\[x=y + 2\]</span></p>
````````````````````````````````
In inline math, the opening `$` must not be followed by
a whitespace, and the closing `$` must not be
preceeded by whitespace.
```````````````````````````````` example
This is not math: 2000$.
And neither is this $ 4 $.
Or this $4
$.
.
<p>This is not math: 2000$.
And neither is this $ 4 $.
Or this $4
$.</p>
````````````````````````````````
Display math delimiters can be surrounded by whitespace:
```````````````````````````````` example
This is display math:
$$
e=mc^2
$$
.
<p>This is display math:
<span class="math display">\[
e=mc^2
\]</span></p>
````````````````````````````````
Note that math can contain embedded math. In scanning
for a closing delimiter, we skip material in balanced
curly braces:
```````````````````````````````` example
This is display math:
$$
\text{Hello $x^2$}
$$
And this is inline math:
$\text{Hello $x$ there!}$
.
<p>This is display math:
<span class="math display">\[
\text{Hello $x^2$}
\]</span>
And this is inline math:
<span class="math inline">\(\text{Hello $x$ there!}\)</span></p>
````````````````````````````````
Display math may contain an unbraced single `$`;
only `$$` closes it:
```````````````````````````````` example
$$a $ b$$
.
<p><span class="math display">\[a $ b\]</span></p>
````````````````````````````````
To avoid treating currency signs as math delimiters,
one may occasionally have to backslash-escape them:
```````````````````````````````` example
The cost is between \$10 and 30$.
.
<p>The cost is between $10 and 30$.</p>
````````````````````````````````
Dollar signs must also be backslash-escaped if they
occur within math:
```````````````````````````````` example
$\text{\$}$
.
<p><span class="math inline">\(\text{\$}\)</span></p>
````````````````````````````````
Everthing inside the math construction is treated
as math, and not given its normal commonmark meaning.
```````````````````````````````` example
$b<a>c$
.
<p><span class="math inline">\(b<a>c\)</span></p>
````````````````````````````````
The inline math closer cannot be immediately followed by a digit.
The opener can be, though.
Display math isn't subject to this rule.
```````````````````````````````` example
$1$2$3
$1$2$3$
$1{$2$}3$
$$1$$2$$3
$$1$$2$$3$$
$$1{$$2$$}3$$
.
<p>$1$2$3</p>
<p>$1$2<span class="math inline">\(3\)</span></p>
<p><span class="math inline">\(1{$2$}3\)</span></p>
<p><span class="math display">\[1\]</span>2$$3</p>
<p><span class="math display">\[1\]</span>2<span class="math display">\[3\]</span></p>
<p><span class="math display">\[1{$$2$$}3\]</span></p>
````````````````````````````````
## TeX comments
Unescaped percent signs start comments through the next newline.
Comment text is preserved, but its braces and dollars do not affect
math boundaries. Escaped percent signs stay literal, and backslashes
inside comments do not escape the newline.
```````````````````````````````` example
$a%$ ignored
+b$
.
<p><span class="math inline">\(a%$ ignored
+b\)</span></p>
````````````````````````````````
```````````````````````````````` example
${a%} $
b}$
.
<p><span class="math inline">\({a%} $
b}\)</span></p>
````````````````````````````````
```````````````````````````````` example
${a%{
b}$
.
<p><span class="math inline">\({a%{
b}\)</span></p>
````````````````````````````````
```````````````````````````````` example
$a\%$
.
<p><span class="math inline">\(a\%\)</span></p>
````````````````````````````````
```````````````````````````````` example
${a\%}$
.
<p><span class="math inline">\({a\%}\)</span></p>
````````````````````````````````
```````````````````````````````` example
$a\%{b$c$}$
.
<p><span class="math inline">\(a\%{b$c$}\)</span></p>
````````````````````````````````
```````````````````````````````` example
$a\\%$
b$
.
<p><span class="math inline">\(a\\%$
b\)</span></p>
````````````````````````````````
```````````````````````````````` example
${a\\%}
b}$
.
<p><span class="math inline">\({a\\%}
b}\)</span></p>
````````````````````````````````
```````````````````````````````` example
$a\\\%$
.
<p><span class="math inline">\(a\\\%\)</span></p>
````````````````````````````````
```````````````````````````````` example
$a%
% } $ \
b$
.
<p><span class="math inline">\(a%
% } $ \
b\)</span></p>
````````````````````````````````
A delimiter inside a final comment cannot close the equation.
```````````````````````````````` example
$a%$
.
<p>$a%$</p>
````````````````````````````````
```````````````````````````````` example
$$a%$$ ignored
+b$$
.
<p><span class="math display">\[a%$$ ignored
+b\]</span></p>
````````````````````````````````
```````````````````````````````` example
$${a%} $$
b}$$
.
<p><span class="math display">\[{a%} $$
b}\]</span></p>
````````````````````````````````
```````````````````````````````` example
$${a%{
b}$$
.
<p><span class="math display">\[{a%{
b}\]</span></p>
````````````````````````````````
```````````````````````````````` example
$$a\%$$
.
<p><span class="math display">\[a\%\]</span></p>
````````````````````````````````
```````````````````````````````` example
$${a\%}$$
.
<p><span class="math display">\[{a\%}\]</span></p>
````````````````````````````````
```````````````````````````````` example
$$a\%{b$$c$$}$$
.
<p><span class="math display">\[a\%{b$$c$$}\]</span></p>
````````````````````````````````
```````````````````````````````` example
$$a\\%$$
b$$
.
<p><span class="math display">\[a\\%$$
b\]</span></p>
````````````````````````````````
```````````````````````````````` example
$${a\\%}
b}$$
.
<p><span class="math display">\[{a\\%}
b}\]</span></p>
````````````````````````````````
```````````````````````````````` example
$$a\\\%$$
.
<p><span class="math display">\[a\\\%\]</span></p>
````````````````````````````````
```````````````````````````````` example
$$a%
% } $$ \
b$$
.
<p><span class="math display">\[a%
% } $$ \
b\]</span></p>
````````````````````````````````
A delimiter inside a final comment cannot close the equation.
```````````````````````````````` example
$$a%$$
.
<p>$$a%$$</p>
````````````````````````````````