Signs of math anxiety (MA) are associated with anxiety and fear before performing mathematical tasks. The aim of the present study was to investigate electrophysiological correlates of conscious and unconscious processes during the performance of simple arithmetic operations depending on the level of math anxiety of study subjects. Study subjects were presented with addition tasks followed by correct and incorrect answers. Study subjects with low levels of MA, both in the block with masked and in the block with unmasked presentation of tasks, demonstrated significant increases in the amplitudes of evoked potentials at 300–400 msec (the N400/P300 wave) on presentation of the correct answer as compared with presentation of the incorrect answer. In the group with high MA levels, this difference was observed only during conscious perception (unmasked presentation of tasks). Study subjects with high MA levels showed a significant difference between correct and incorrect answers at 450–650 msec during unconscious perception of tasks, suggesting that the late positive component (LPC) wave had an arithmetic effect. Thus, these results may indicate predominant use of procedural strategies for solution of simple tasks by study subjects with high MA levels. On the other hand, study subjects with low MA levels demonstrated correlates of automatic retrieval of answers directly from long-term memory, even with unconscious perception of stimuli.