title: I have a date variable and I've never seen the numbers like this.. can someone explain
body: <pre><code>$last = $today - (60*60*24*90); //90 days ago
  </code></pre>
  
  <p>Obviously i see the commented out line that says this is equivalent to 90 days but can someone explain exactly what each number is doing.</p>
  
  <p>The asterisk is multiplying each number but it's confusing. Is that seconds or microseconds?</p>
  
  <p>Thanks in advance.</p>