If I remember back to Q Basic days there was a Left$ or Right$ and number of characters command, but I cant see anything like that in PBP.
Nope...

Try something like this.
IF NUM_REM >= 9999 and <= 1000 THEN
DIG3 NUM_REM

IF NUM_REM >= 999 and <= 100 THEN
DIG2 NUM_REM