table{
  margin: auto;
  border-radius: 10px;
  background-color: rgba(150,150,150,0.8);
  height: 200px;
  width: 200px;
}
body{
  background: url('https://wallpaper.dog/large/5529077.jpg');
  background-size: contain;
}
.clear{
  background-color: yellow;
}
.operators{
  background-color: orangered;
  font-weight: bold;
  font-size: 80%;
}