JSFiddle - React, Tailwind, and code Playground

HTML

<div class="switch">
<div class="avg_words float_left">
  A+ (hover to see score)  
</div>
<div class="avg_num">
  AVG = 98.35%
</div>
</div>

CSS

.avg_num {
	display: none;
}

.switch:hover .avg_words{
  display: none;
}
.switch:hover .avg_num{
  display: block;
}