utton class="key" type="button">7</button>
          </div>
          <div class="pad__slot r1 c1">
            <button class="key" type="button">8</button>
          </div>
          <div class="pad__slot r1 c2">
            <button class="key" type="button">9</button>
          </div>
          <div class="pad__slot r1 c3">
            <button class="key" type="button">-</button>
          </div>

          <div class="pad__slot r2 c0">
            <button class="key" type="button">4</button>
          </