<div>
<a href="tel:+7644664">+7 (64) 46-64</a>
<br>
<a href="tel:+7644664">+7 (64) 46-64</a>
<br>
<a href="tel:+7644664">+7 (64) 46-64</a>
<br>
<a href="tel:+7644664">+7 (64) 46-64</a>
</div>

div {
  font-size: 1.1em;
  line-height: 1.5;
  }
div a {
  color: #000;
  text-decoration: none;
  border-bottom: 1px dashed #000;
  -webkit-transition: all .4s ease;
          transition: all .4s ease;
  }
div a:hover {
  color: #25c019;
  border-bottom: 1px dashed #25c019;
  }