Hi isaac,
"cutting off" is easily achieved by rounding... (Attachment). But you loose precision - maybe it's needed for some following calculations?
To show a vi when called as subvi you have to switch on "show front panel when called" and "close afterwards...", no need for "run when opened" or "show front panel when loaded"!
Best regards,
GerdW

using LV2016/2019/2021 on Win10/11+cRIO, TestStand2016/2019