.box {
  border: 2px solid black;
  width: 210px;
  height: 210px;
  float: left;
}

.cell {
  border: 1px solid black;
  width: 70px;
  height: 70px;
  float:left;
  box-sizing: border-box;

  font-size: 40px;
  font-weight: bold;
  display: flex;
  align-items: center;
  justify-content: center;
}

.cell > span {
  font-size: 12px;
  font-weight: normal;
  text-align: center;
  letter-spacing: 11px;
  word-wrap: anywhere;
  padding-left: 10px;
}