title: Round to nearest multiple of a number
body: <p>Is there an idiomatic way to round to the <strong>nearest</strong> multiple of a number, short of rounding both up and down and seeing which one is closest?</p>
  
  <p>Assume only integers:</p>
  
  <pre><code>number   multiple   result
  12       5          10
  13       5          15
  149      10         150
  </code></pre>