JSFiddle - React, Tailwind, and code Playground

HTML

<table border="0" width="">
<tr>
  <td>Montag</td>
  <td>Dienstag</td>
  <td>Mittwoch</td>
</tr>
<tr>
  <td>100</td>
  <td>200</td>
  <td>300</td>
</tr>
<tr>
  <td class="noborder">100</td>
  <td>200</td>
  <td class="noborder">300</td>
</tr>
</table>

CSS

td {
  border:1px solid gray;
}
td.noborder {
  border:none !Important;
}