We propose a novel triple-gated single transistor comprising monolayer MoS2 channel to accomplish basic logic-gate functions. The NAND and NOR computing are compatible in the same MoS2 n-FET and switchable easily through top-gate bias setting (VLOW / VHIGH = 0.75V / 2V). Moreover, separated top- and back-gate (TG and BG) operations in proposed device also enable the modulation of ON-state resistance by 7 orders of magnitude with maintaining low OFF-state current. The electrical response in devices with various back-gate designs could be explained in terms of energy band diagram through TCAD simulation. In this work, the multi-gated MoS2 n-FETs have successfully demonstrated good logic-gate operation and large ON-OFF ratio modulation, which provide a new perspective in device design for future logic and even in-memory computing applications.