<div class="container">
  <div class="item-1">125px</div>
  <div class="item-2">125px</div>
  <div class="item-3">125px</div>
  <div class="item-4">125px</div>
</div>

.container {
  display:flex;
  border: 1px solid #111;
  width:500px;
  height:200px;
}

.container > div {
  height:100px;
  display:flex;
  justify-content:center;
  align-items:center;
  flex:1;
}

.item-1 {
  width:100px;
  background-color:coral;
}

.item-2{
  width:125px;
  background-color:chocolate;
}

.item-3{
  width:75px;
  background-color: violet;
}

.item-4{
  width:50px;
  background-color:orange;
}