Abstract: Apparatus for computing an arithmetically accumulated sequence of exponenantissa formatted numbers, which comprises write-in apparatus and read-out apparatus. The write-in apparatus comprises means for separating each of a sequence of numbers in exponent-mantissa form according to the values of the exponent, the value of the exponent being employed as a storing address for the number. Means connected to the separating means algebraically sum mantissas of like exponents; the two above means comprising a write logic block. A random-access memory is connected to the summing means for storing the sum of the mantissas. It also includes means for addressing the storing means.