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copied!<p>For a number to be even it must end with an even digit. Even digits are 0, 2, 4, 6, and 8. Use a character class to specify which digits are allowed at each position.</p> <p>The answer is:</p> <pre><code>/^[0-9]*[02468]$/ </code></pre> <p>Explanation:</p> <pre> ^ Start of line/string [0-9] Any digit from zero to nine. * Repeat the last token zero or more times. [02468] Any even digit. $ End of line/string. </pre> <p>To help you learn regular expressions I would recommend reading the <a href="http://www.regular-expressions.info/quickstart.html" rel="noreferrer">Regular Expression Quick Start</a>.</p> <p>You may also see <code>\d</code> used instead of <code>[0-9]</code>. In some regular expression engines these are equivalent, but in others <code>\d</code> also matches characters which are regarded as numerals in foreign countries.</p> <p><strong>For more information</strong></p> <ul> <li><a href="http://www.regular-expressions.info/charclass.html" rel="noreferrer">Character classes</a></li> <li><a href="http://www.regular-expressions.info/anchors.html" rel="noreferrer">Anchors</a></li> <li><a href="http://www.regular-expressions.info/repeat.html" rel="noreferrer">Quantifiers</a></li> </ul> <p>As an exercise you could try to work out how to adjust this regular expression to disallow leading zeros. Hint: there are three types of digit: the first digit, the middle digits, the last digit. Remember that only the last digit must be present, the others are optional.</p>

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