Edit in JSFiddle

<ul class="flex-container row justify-start">
  <li class="flex-item">1</li>
  <li class="flex-item">2</li>
  <li class="flex-item">3</li>
  <li class="flex-item">4</li>
  <li class="flex-item">5</li>
</ul>

<ul class="flex-container row justify-end">
  <li class="flex-item">1</li>
  <li class="flex-item">2</li>
  <li class="flex-item">3</li>
  <li class="flex-item">4</li>
  <li class="flex-item">5</li>
</ul>

<ul class="flex-container row justify-center">
  <li class="flex-item">1</li>
  <li class="flex-item">2</li>
  <li class="flex-item">3</li>
  <li class="flex-item">4</li>
  <li class="flex-item">5</li>
</ul>

<ul class="flex-container row justify-space-between">
  <li class="flex-item">1</li>
  <li class="flex-item">2</li>
  <li class="flex-item">3</li>
  <li class="flex-item">4</li>
  <li class="flex-item">5</li>
</ul>

<ul class="flex-container row justify-space-around">
  <li class="flex-item">1</li>
  <li class="flex-item">2</li>
  <li class="flex-item">3</li>
  <li class="flex-item">4</li>
  <li class="flex-item">5</li>
</ul>

.flex-container {
  padding: 0;
  margin: 0;
  list-style: none;
  
  -ms-box-orient: horizontal;
  display: -webkit-box;
  display: -moz-box;
  display: -ms-flexbox;
  display: -moz-flex;
  display: -webkit-flex;
}
.justify-start {
	justify-content: flex-start; 
}

.justify-end {
	justify-content: flex-end; 
}
.justify-end li{
	background: gold; 
}

.justify-center {
	justify-content: center; 
}
.justify-center li{
	background: lightgreen; 
}

.justify-space-between {
	justify-content: space-between; 
}
.justify-space-between li{
	background: deepskyblue; 
}

.justify-space-around {
	justify-content: space-around; 
}
.justify-space-around li{
	background: #F06292; 
}

.row           { 
  -webkit-flex-direction: row; 
  flex-direction: row;
  flex-wrap: normal;
}

.flex-item {
  background: tomato;
  padding: 5px;
  width: 50px;
  height: 50px;
  margin: 5px;
  
  line-height: 50px;
  color: white;
  font-weight: bold;
  font-size: 2em;
  text-align: center;
}