Edit in JSFiddle

<div class="flex-container">
<div class="item item1">1</div>
<div class="item item2">2</div>
<div class="item">3</div>
<div class="item item4">4</div>
<div class="item">5</div>
</div>

*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
*::before, *::after{
  box-sizing: border-box;
}
.flex-container{
  display: flex;
flex-direction: row-reverse;
padding: 15px;
border: 1px solid #e2e2e2;
}
.item{
  background-color: #2da192;
  text-align: center;
  height: 100px;
  line-height: 100px;
  font-size: 30px;
  margin: 5px;
  font-weight: 600;
  color: #fff;
  width: 100px;
}