(Converge to 0)</td>
  </tr>
  <tr class="odd">
  <td><kbd>z</kbd></td>
  <td>Undo</td>
  </tr>
  <tr class="even">
  <td><kbd>Z</kbd></td>
  <td>Redo</td>
  </tr>
  <tr class="odd">
  <td><kbd>,</kbd> (Comma)</td>
  <td>Rotate Back</td>
  </tr>
  <tr class="even">
  <td><kbd>.</kbd> (Period)</td>
  <td>Rotate Forward</td>
  </tr>
  <tr class="odd">
  <td><kbd>1</kbd></td>
  <td>Decrease</td>
  </tr>
  <tr class="even">
  <td><kbd>2</kbd>-<kbd>4</kbd></td>
  <td>Decrease 2n-4n</td>
  </tr>
  <tr class="odd"