Every retailer is required to keep records in order to determine the amount of tax due.
These records must include the normal books of account ordinarily maintained by the average prudent businessman engaged in a similar activity, together with all documents supporting entries in the books of accounts. Schedules and working papers used in the preparation of the tax re turns and all resale certificates and exemption certificates must be retained. The records created at the time of sale may take the form of sales slips, sales invoices, guest checks, tally sheets, itemized lists, or other memoranda. A cash register tape may be acceptable if it preserves sufficient information. Items may be described by a symbol if the symbol is representative of a class of merchandise or services which are always taxable or exempt.