title: A non well formed numeric value encountered on if condition
body: <p>this if condition throw "A non well formed numeric value encountered" message. </p>
  
  <pre><code>if(strtotime($from) + $conHour*60*60 == strtotime($to)){
  
  }
  </code></pre>
  
  <p>The error I see is:</p>
  
  <blockquote>
    <p>A non well formed numeric value encountered</p>
  </blockquote>
  
  <p>****var_dump** </p>
  
  <pre><code>$from = string(19) "2019-04-15 16:05:00"    
  $to =string(19)"2019-04-15 17:05:00"    
  $conhour = string(5) "01:00"
  </code></pre>