Customize number column to remove the commas and to choose the number of digits needed from the form fillers

The number column works but we need to be able to customize the column recieve a specified number of digits to ensure that the respondents of the forms do not enter the wrong number on the form. For example, when the number required is sjust 4 digits, we need to be able to set the form to recieve only 4 digits after which it will indicate to the respondent that the number is incorrect as it has exceeded the values required