>100 or @value@>100 in the Custom box.
==To limit a date to the future==
ConvertDateStr(@value@,"@dateformat@")>''date''
'''Where'''
''date'' is a date in the format YYYY-MM-DD
'''Example'''
To limit the date to a future date greater than today
ConvertDateStr(@value@,"@dateformat@")>"@YEAR(currendate)@-@MONTH(currentdate)@-@DAY(currentdate)@"
==To limit the amount of characters that can be entered into a field==