display watch or digital clock

Just for an OOTB example, I implemented something for a similar requirement with a!gaugeField() for a countdown timer in a Meeting Minute type app:

/* rule inputs are datetime */

a!localVariables(
  local!notSet: or(
    rule!APN_isEmpty(ri!start),
    rule!APN_isEmpty(ri!end),
    rule!APN_isEmpty(ri!current),
    ri!current<ri!start
  ),
  local!hours: if(local!notSet,0,hour(tointervalds(ri!end-ri!start))),
  local!minutes: if(local!notSet,0,minute(tointervalds(ri!end-ri!start))),
  local!duration: if(local!notSet,0,(local!hours*60)+local!minutes),
  local!curHoursIn: if(local!notSet,0,hour(tointervalds(ri!current-ri!start))),
  local!curMinutesIn: if(local!notSet,0,minute(tointervalds(ri!current-ri!start))),
  local!durationIn: if(local!notSet,0,(local!curHoursIn*60)+local!curMinutesIn),
  local!remainingMinutes: if(local!notSet,0,if(local!durationIn>local!duration,0,local!duration-local!durationIn)),
  local!pct: if(local!notSet,0,trunc((local!durationIn/local!duration)*100,0)),

  {
    a!gaugeField(
      labelPosition: "COLLAPSED",
      percentage: local!pct,
      primaryText: if(local!notSet,"---",local!remainingMinutes),
      secondaryText: "mins remain",
      color: rule!MM_getGaugeColorForPct(
        pct: local!pct,
        notSet: local!notSet
      ),
      size: "MEDIUM",
      align: "CENTER",
    )
  }
)

Helper rule!MM_getGaugeColorForPct() (this could be optimized..):

if(
  ri!notSet,
  "#afafaf",
  if(
    ri!pct < 20,
    "#008000",
    if(
      and(
        ri!pct >= 20,
        ri!pct < 40
      ),
      "#a4d100",
      if(
        and(
          ri!pct >= 40,
          ri!pct < 60
        ),
        "#f9fc00",
        if(
          and(
            ri!pct >= 60,
            ri!pct < 80
          ),
          "#ff8500",
          if(
            ri!pct >= 80,
            "#ff0500",
            "#afafaf"
          )
        )
      )
    )
  )
)

Could not display interface. Please check definition and inputs. Interface Definition: Expression evaluation error at function 'trunc' parameter 1 [line 16]: Invalid division: Denominator may not be zero (0)

it is not working its giving me this error

Could not display interface. Please check definition and inputs. Interface Definition: Expression evaluation error at function 'trunc' parameter 1 [line 16]: Invalid division: Denominator may not be zero (0)

it is not working its giving me this error

The error is pretty clear. What problem are you facing in resolving this?