<div class="block">
  <div class="block__item"></div>
  <div class="block__item"></div>
  <div class="block__item"></div>
  <div class="block__item"></div>
  <div class="block__item"></div>
</div>
.block {
  border: 1px solid red;
  display: flex;
  flex-wrap: wrap;
  /*padding: 5px 3px 5px 5px;*/
  max-width: 900px;
  justify-content: flex-start;
  justify-content: space-between;

}

.block__item {
  background: grey;
  height: 20px;
  margin-bottom: 5px;
  /*width: calc(33.33% - 8px);*/
  /*margin-right:8px;  */
  flex: 0 0 32%;
}

/*.block__item:nth-child(3n){
  margin-right:0; 
}*/
Run Pen

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.