title: Regular Expression to match 3 to 4 digits
body: <p>I am learning regular expressions and I am trying find this string day1otlk_XXXX.gif
  where the 4 X's will be 3 to 4 random digits. This is what I have so far am I close?</p>
  
  <pre><code>qr/day1otlk_\d++\.gif/i
  </code></pre>