This study applied two arithmetic tests, one written and one computer-based interactive, to samples of primary school children from two populations, one suburban non-Aboriginal and one rural Aboriginal. The results from the written test were significantly (p<0.001) better for the non-Aboriginal children than for the Aboriginal children. This was not the case with the results from the computer-based interactive test. The study used Rasch-based methodology to reduce the results from the two tests to a common scale, to ascertain whether the Aboriginal children performed better (in relation to the non-Aboriginal children) in the computer-based than in the written test. The study found that this was the case, and concluded that the results from the computer-based test exhibited less cultural bias against the Aboriginal children than the written test.