<div class="box1">Specify width by addition</div>
<div class="box2">Specify width by subtraction</div>
<div class="box3">Specify width by multiplication</div>
<div class="box4">Specify width by division</div>
/* Addition */
.box1{
  width: calc(100px + 50px);
}
/* subtraction */
.box2{
  width: calc(200px - 50px);
}
/* multiplication */
.box3{
  width: calc(75px * 2);
}
/* division */
.box4{
  width: calc(300px / 2);
}

div{
  background: #ccc;
  text-align: center;
  font-size: 12px;
  padding: 10px 0;
  margin: 0 0 5px;
}

External CSS

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External JavaScript

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