Across two experiments involving four conditions, Sklar et al. (2012) found that complex subtraction equations can be solved without awareness of the equations. These findings challenge the current position that consciousness is necessary for performing abstract, rule‐following tasks. Given the important implications of their work, we directly replicate Sklar's findings using a larger sample (n = 94) from a different population. Using Continuous Flash Suppression, we investigated if people were able to solve an equation after subliminal (1300 ms) exposure to it. We found evidence for unconscious addition but not subtraction. The effect of unconscious addition was eliminated when participants reported subjective awareness of the primes. Critical review of our results and implications for further research are discussed.