showing players health with one decimal?

First of all, let's make sure your script doesn't run before the LocalPlayer loads. To do that, we can use the following loop: repeat wait() until game.Players.LocalPlayer.Character;

Next, I inserted a function called round1Place, that you call with round1Place(NUMBERHERE) and it returns the same number but rounded to the first decimal point.

For example:

function round1Place(x)
	return (x + 0.05 - (x + 0.05)  % .1)
end
local r = 3.32
r = round1Place(r)
print(r) --> 3.3

print(round1Place(2.25)) --> 2.3

Put it all together:

repeat wait() until game.Players.LocalPlayer.Character;
humanoid = game.Players.LocalPlayer.Character.Humanoid
function round1Place(x)
	return (x + 0.05 - (x + 0.05)  % .1)
end

while wait() do  
	script.Parent.Text = round1Place(humanoid.Health)
end