Formatting a value

I am using:
[$SCRIPT=&nhs.TimerValue("Test").TotalMinutes()]
in a HSTouch text box to show the time in minutes. The value that is displayed has 8 decimal places. How can I use a format function to control how the value is displayed as to setting the number of digits both to the left and right of the decimal place? I would also like to be able to either show or not show leading zeros.

I would much appreciate an example of how I can format the value.
Wallis