Neb. Admin. Code § 350-14-002.03 — Actual Value shall mean the market value of real property in the ordinary course of trade

It is the most probable price expressed in terms of money that a property will bring if exposed for sale in the open ma rket in an arm's -length transaction between a willing seller and a willing buyer, both of whom are knowledgeable concerning all the uses to which the real property is adapted and for which it is capable of being used. Actual value may be determined using professionally accepted mass appraisal methods, including, but not limited to the (1) sales comparison approach, (2) income approach, and (3) cost approach.