<div class="box">
  <div class="item">1</div>
  <div class="item">2</div>
  <div class="item">3</div>
  <div class="item">4</div>
  <div class="item">5</div>
  <div class="item">6</div>
  <div class="item">7</div>
  <div class="item">8</div>
  <div class="item">9</div>
</div>
.box {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  grid-column-gap: 2px;
  grid-row-gap: 42px;
}

.box .item {
  background-color: tomato;
  color: white;
  font-size: 1.4em;
  font-family: monospace;
  padding: 16px;
}

.box .item:nth-child(1),
.box .item:nth-child(2),
.box .item:nth-child(3) {
  position: relative;
}

.box .item:nth-child(1)::after,
.box .item:nth-child(2)::after,
.box .item:nth-child(3)::after {
  content: "42px";
  display: block;
  position: absolute;
  bottom: -32px;
  left: 40%;
  color: #111;
  font-size: .87em;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.