It is commonly held that numbers and number expressions constitute the first universal language independent of any natural language. No doubt has been cast on the notion that mother tongue differences make no difference in learning mathematics. Because of its "universal" character, mathematics was chosen as the subject to be investigated in the IEA International Study of Educational Achievement. A defect in this study, however, is the failure to take into account the cultural background of the participating countries. For example, the mathematical expression "2 x 3," is believed by IEA examiners to express an identical concept universally. However, it does not. In English, it generally means "2 times 3," namely "3 + 3." In Japan, it means "2 no 3 bai," or "2 + 2 + 2." That is, the positions of the multiplier and the multiplicand are reversed, because there is no equivalent way of expressing "A times B" in Japanese. When the number system, multiplication tables and mathematical expressions are thus considered, mathematics remains an artificial language not fully independent of natural languages, rather than the ideal medium modern science is searching for. The results of the IEA test will reflect not only the degree of achievement in mathematics, but also features of the examinee's own language and culture as a background. (Author/CLK)