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<title>Arithmetic Operators</title>
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<h2 class="title">Arithmetic Operators</h2>
<p class="simpara">
Remember basic arithmetic from school? These work just
like those.
</p>
<table class="doctable table">
<caption><strong>Arithmetic Operators</strong></caption>
<thead>
<tr>
<th>Example</th>
<th>Name</th>
<th>Result</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>-$a</td>
<td>Negation</td>
<td>Opposite of <var class="varname"><var class="varname">$a</var></var>.</td>
</tr>
<tr>
<td>$a + $b</td>
<td>Addition</td>
<td>Sum of <var class="varname"><var class="varname">$a</var></var> and <var class="varname"><var class="varname">$b</var></var>.</td>
</tr>
<tr>
<td>$a - $b</td>
<td>Subtraction</td>
<td>Difference of <var class="varname"><var class="varname">$a</var></var> and <var class="varname"><var class="varname">$b</var></var>.</td>
</tr>
<tr>
<td>$a * $b</td>
<td>Multiplication</td>
<td>Product of <var class="varname"><var class="varname">$a</var></var> and <var class="varname"><var class="varname">$b</var></var>.</td>
</tr>
<tr>
<td>$a / $b</td>
<td>Division</td>
<td>Quotient of <var class="varname"><var class="varname">$a</var></var> and <var class="varname"><var class="varname">$b</var></var>.</td>
</tr>
<tr>
<td>$a % $b</td>
<td>Modulus</td>
<td>Remainder of <var class="varname"><var class="varname">$a</var></var> divided by <var class="varname"><var class="varname">$b</var></var>.</td>
</tr>
</tbody>
</table>
<p class="simpara">
The division operator ("/") returns a float value unless the two operands
are integers (or strings that get converted to integers) and the numbers
are evenly divisible, in which case an integer value will be returned.
</p>
<p class="simpara">
Operands of modulus are converted to integers (by stripping the decimal
part) before processing.
</p>
<p class="para">
The result of the modulus operator <em>%</em> has the same sign
as the dividend — that is, the result of <em>$a % $b</em>
will have the same sign as <var class="varname"><var class="varname">$a</var></var>. For example:
<div class="informalexample">
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br /></span><span style="color: #007700">echo (</span><span style="color: #0000BB">5 </span><span style="color: #007700">% </span><span style="color: #0000BB">3</span><span style="color: #007700">).</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">; </span><span style="color: #FF8000">// prints 2<br /></span><span style="color: #007700">echo (</span><span style="color: #0000BB">5 </span><span style="color: #007700">% -</span><span style="color: #0000BB">3</span><span style="color: #007700">).</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">; </span><span style="color: #FF8000">// prints 2<br /></span><span style="color: #007700">echo (-</span><span style="color: #0000BB">5 </span><span style="color: #007700">% </span><span style="color: #0000BB">3</span><span style="color: #007700">).</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">; </span><span style="color: #FF8000">// prints -2<br /></span><span style="color: #007700">echo (-</span><span style="color: #0000BB">5 </span><span style="color: #007700">% -</span><span style="color: #0000BB">3</span><span style="color: #007700">).</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">; </span><span style="color: #FF8000">// prints -2<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="simpara">
See also the manual page on
<a href="ref.math.html" class="link">Math functions</a>.
</p>
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