IQ was originally computed by taking the ratio of mental age to chronological (physical) age and multiplying by 100. Thus, if a 10-year-old child had a mental age of 12 (that is, performed on the test at the level of an average 12-year-old), the child was assigned an IQ of ¹²/₁₀ × 100, or 120. If the 10-year-old had a mental age of 8, the child's IQ would be ⁸/₁₀ × 100, or 80. Based on this calculation, a score of 100—where the mental age equals the chronological age—would be average. Few tests continue to involve the computation of mental ages. See also Lewis Terman (Terman, Lewis Madison); Alfred Binet (Binet, Alfred).