Two HTML tables side by side, centered on the page

I have two tables on a page that I want to display side by side, and then center them within the page (actually within another div, but this is the simplest I could come up with):

<style>
  #outer { text-align: center; }
  #inner { text-align: left; margin: 0 auto; }
  .t { float: left; }
  table { border: 1px solid black; }
  #clearit { clear: left; }
</style>

<div id="outer">
  <p>Two tables, side by side, centered together within the page.</p>

  <div id="inner">
    <div class="t">
      <table>
        <tr><th>a</th><th>b</th></tr>
        <tr><td>1</td><td>2</td></tr>
        <tr><td>4</td><td>9</td></tr>
        <tr><td>16</td><td>25</td></tr>
      </table>
    </div>

    <div class="t">
      <table>
        <tr><th>a</th><th>b</th><th>c</th></tr>
        <tr><td>1</td><td>2</td><td>2</td></tr>
        <tr><td>3</td><td>5</td><td>15</td></tr>
        <tr><td>8</td><td>13</td><td>104</td></tr>
      </table>
    </div>

  </div>
  <div id="clearit">all done.</div>
</div>

I understand that it's something to do with the fact that the tables are floated, but I'm at a loss as to understand what I'm missing. There are many web pages that describe something like the technique I show here, but in any event it doesn't work; the tables cling stubbornly to the left hand margin.