Blizzhackers

Hi, what function of FontString should I use to make spaces between chars in FontString?
I have 0-9 buttons and after click, the number of button appears in the FontString. My problem is numbers are always overwritted, i want to add number next to previous one.
In the previous version of my Addon ( ) i used EditBox, there was Insert function.

Edit: I resolved my problem.
s = FontString1:GetText()
FontString1:SetText(s*10+1);