Go to Administration -> CRM preferences -> General and check Add ‘Street number’ field. Street number will than be a separate field on all contact cards in the database. When this field is disabled, please add the contact’s street numbers into the street address field.

Note: We advise you not to use the separate street number field option when you use the contacts-sync on your phone as well. Apple does not use street number as separate field, so this the information is not properly synced between your devices.