All-optical processor capable of processing optical bits has been a long-standing goal of photonics. In this paper, we report the results obtained by numerical simulations regarding the designing of an all-optical combinational circuit of an adder and subtractor circuits based on Si3N4 microring resonators. The designs of combinational circuit like adders and subtractor based on the use of all-optical basic logic gates are discussed while presenting the numerically simulated results. Extinction ratios of 5.2 dB, 3.5 dB and 2.7 dB are obtained for the half adder, full adder and half subtractor, respectively.