A Compute-In-Memory (CIM) architecture includes a plurality of memories and a plurality of processing elements. Each of the processing elements has a look-up table unit configured to store values of a look-up table of a k-cluster residue number system, and output one of the values of the look-up table according to a first remainder and a second remainder as a result of a residue calculation. The look-up table unit receives the first remainder and the second remainder from one of the memories.

An arithmetic processing device includes: a first multiplier circuit configured to calculate a product DY of an approximate value D obtained by approximating a reciprocal 1/Y of a divisor Y; a dividend operation circuit configured to compare a dividend X and the divisor Y, and generate an operation value twice the dividend X or the operation value equal to the dividend X based on a comparison result; a second multiplier circuit configured to calculate a product of the approximate value D and the operation value as an initial value R(0) of a partial remainder R(n); a third multiplier circuit configured to calculate a product DY*q(n) of the product DY and a partial quotient q(n) that is a predetermined number of upper bits of the partial remainder R(n); and a first addition circuit configured to calculate a new partial remainder R(n) by subtracting the product DY*q(n) from the partial remainder R(n).