This report: (1) describes the mathematics test given to Year 9 students in the Mt. Druitt Longitudinal Study in 1987; (2) describes and discusses the results; (3) analyzes errors made by students; (4) analyzes the responses to items common to the 1986 and 1987 tests; and (5) suggests some interventions to address the errors made by students. The study dates from 1975 when funds were obtained to provide intervention programs at five preschools in Mt. Druitt (Australia), an area which had been identified as being disadvantaged. These intervention programs were aimed at bridging the educational achievement gap between these "disadvantaged" students and those who were not "disadvantaged." The intervention programs ceased in 1979 when the children had completed first grade. Since that time the study has been involved in assessing educational skills, pupil attitudes, and teacher and pupil classroom behavior through testing, questionnaires, and observation. Teacher and parent interviews have also been conducted. To determine whether the early intervention assisted the Mt. Druitt students, comparison schools were chosen to undergo the same testing as the Mt. Druitt schools. In 1987, the students who were identified in 1977 were in year 9 in high school. Scripts of the 1987 test, which was administered in two parts on separate occasions within one school week in April, are appended. (PK)