The purpose of this study was to gather descriptive data about the mathematics achievement levels of students in grades 6 and 8 in 1973 for comparisons to data from 1936, 1951-55, and 1965. Among the areas identified for comparisons were whole number computation, fractional equivalents, problem solving, computation involving compound denominate numbers, ratios and proportions, geometrical and measurement concepts, numeration, and number systems. The Iowa Tests of Basic Skills items from past years were readministered to classes chosen from representative Iowa schools. Intact tryout units, the same testing format, and the same testing procedures as in the past were used. Among the results were: (1) achievement in grades 6 and 8 in 1973 was clearly inferior to achievement in 1936 in problem solving; computation with whole numbers and fractions; decimals, percentages, and fractional parts; (2) achievement in 1973 was inferior to achievement in 1951-55 in computation with whole numbers and fractions at grade 6, and decimals, percentages, and problem solving at grade 8; and (3) achievement in grades 6 and 8 in 1973 was inferior to achievement in 1965 in problem solving. (Author/DT)