variable operation with negative operator

[tek]

hello,

I want to get the current time minus 15 minutes

I do this with a variable operation:$minute$ - 15 To myMinutes and then I check if myMinutes is less than 0

if it is less than zero, I add 60 to it ($myMinutes$ + 60 to $myMinutes$) and subtract 1 from $hour$

the problem is that $myMinutes$ is '-4 + 60' instead of 56

is there a solution to this problem?

thanks

Joris

working with automation anywhere 4.5 premier