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<p><strong>Reference</strong> <a class='wikilink' href='index.html'>Language</a> | <a class='wikilink' href='Libraries.html'>Libraries</a> | <a class='wikilink' href='Comparison.html'>Comparison</a> | <a class='wikilink' href='Changes.html'>Changes</a>
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<p class='vspace'></p><h2>Addition, Subtraction, Multiplication, & Division</h2>
<h4>Description</h4>
<p>These operators return the sum, difference, product, or quotient (respectively) of the two operands. The operation is conducted using the data type of the operands, so, for example, <code>9 / 4</code> gives <code>2</code> since 9 and 4 are ints. This also means that the operation can overflow if the result is larger than that which can be stored in the data type (e.g. adding 1 to an <a class='wikilink' href='Int.html'>int</a> with the value 32,767 gives -32,768). If the operands are of different types, the "larger" type is used for the calculation.
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<p class='vspace'></p><p>If one of the numbers (operands) are of the type <strong>float</strong> or of type <strong>double</strong>, floating point math will be used for the calculation.
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<p class='vspace'></p><h4>Examples</h4>
<pre>
y = y + 3;
x = x - 7;
i = j * 6;
r = r / 5;
</pre>
<p class='vspace'></p><h4>Syntax</h4>
<pre>
result = value1 + value2;
result = value1 - value2;
result = value1 * value2;
result = value1 / value2;
</pre>
<p class='vspace'></p><h4>Parameters:</h4>
<p>value1: any variable or constant
</p>
<p class='vspace'></p><p>value2: any variable or constant
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<p class='vspace'></p><h4>Programming Tips:</h4>
<ul><li>Know that <a class='wikilink' href='IntegerConstants.html'>integer constants</a> default to <a class='wikilink' href='Int.html'>int</a>, so some constant calculations may overflow (e.g. 60 * 1000 will yield a negative result).
<p class='vspace'></p></li><li>Choose variable sizes that are large enough to hold the largest results from your calculations
<p class='vspace'></p></li><li>Know at what point your variable will "roll over" and also what happens in the other direction e.g. (0 - 1) OR (0 - - 32768)
<p class='vspace'></p></li><li>For math that requires fractions, use float variables, but be aware of their drawbacks: large size, slow computation speeds
<p class='vspace'></p></li><li>Use the cast operator e.g. (int)myFloat to convert one variable type to another on the fly.
</li></ul><p class='vspace'></p><p><a class='wikilink' href='index.html'>Reference Home</a>
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<p class='vspace'></p><p><em>Corrections, suggestions, and new documentation should be posted to the <a class='urllink' href='http://arduino.cc/forum/index.php/board,23.0.html' rel='nofollow'>Forum</a>.</em>
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<p class='vspace'></p><p>The text of the Arduino reference is licensed under a
<a class='urllink' href='http://creativecommons.org/licenses/by-sa/3.0/' rel='nofollow'>Creative Commons Attribution-ShareAlike 3.0 License</a>. Code samples in the reference are released into the public domain.
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