title: PHP Convert separate day,month and year to date
body: <p>I looked in many threads regarding this issue but still can't get to the bottom of this one. Here is my code:</p>
  
  <pre><code>$birthdate_ts = strtotime("$year-$num_month-$day");
  $birthdate = date("d/m/Y",$birthdate_ts);
  </code></pre>
  
  <p>Where $day $num_month and $year are numbers (example 1 10 1990).
  The result I'm getting is 1/1/1970 every time. I also tried different variations for the "strtotime()" input and still nothing.
  Where am I wrong?</p>