[AccessD] A2003: Showing to 4 decimal places

Hi All
 
<sigh> brain fade here - what is the correct syntax to show a display up to 4
decimal places
 
But some numbers will genuinely be 1, 2 or 3 decimal places and as such only
need to show 1, 2 or 3 decimal places respectively
 
Many thanks in advance
 
Darren