Here's a Quick Tip for newcomers...

When you add a slider control to a dashboard, it will probably look like one of these:

... depending on how much room (width & height) you've given it. There are a few things to note. First, currently you can not format the font in the readout box. You also can not change the proportions of the readout box size compared to the slider and button controls. The readout will take 50% of the real estate even when it is only a single digit, as in (a). Or the full width, as in (b).

But with just a little work (and a bit of trickery), you can make it look like this:

Here are the steps:

Final note: You may have noticed this is a slider for a parameter. Parameters appear automatically in the Insert list, but filters don't. So if you're using filters then you have a bit more work to do between step 2 & 3. The 'more work' is dependent on your situation, and probably starts with dropping a measure on the level of detail shelf, but this can have other consequences, which need other tricks to deal with. So I'll leave that part for another quick tip. Hope this helps you enjoy using Tableau as much as I do.

--Shawn

PS: If you want to see the overall viz I used this technique for, go here.