There's a little-known option FloatToString$(), which you can find under the System object Conversion expressions.
Originally Posted by logum5
Put the number into the Value parameter. FloatToString will be in the Fusion help file if you need more detail.
FloatToString$(>Value<, >Number of digits<, >Number of digits after decimal point or -1<)
If you don't want to use that, you could also use
...but it's a bit more fiddly.
On a side note, this forum is more for getting extension developers, not for Fusion issues. Next time ask in the Fusion 2.5 forum.
(If you do need help with developing your own extension, clarify which coding language you want and more context for the decimal places)