How do I get the value of a slider?

I am a beginner to Unity. I want to display the current value of a slider as text. I've looked for answers on my own for an hour and can't make it work. It looks like you're supposed to create a public variable like,

 public Slider sliderName;

then just use

 variable = sliderName.value;

to get the value out. But every time I try that it gives me an error ( 'Slider' does not contain a definition for 'value'). It looks like nobody else is having this problem so I assume I'm doing something stupid. I'm already using UnityEngine.UI so that isn't the problem.