Mathematics is a very important subject in Nigeria. Yet, for more than twenty years, mathematics education in Nigeria has been in a sorry state. Mathematics achievement has been very low and frustrating. So far, every effort made to save Nigerian education from the devastating effect of persistent poor mathematics achievement has failed. An experiment to address the problem of poor achievement in mathematics in Nigerian high schools was carried out in Edo State of Nigeria. Eighteen simple improvised geometric manipulatives were made from ordinary cardboard paper. The manipulatives were used in teaching students in experimental group. There was a control group of students which did not study with manipulatives. Scores were collected from mathematics test taken by students in both experimental and control groups. Statistical analysis showed that students in the experimental group (who were taught with manipulatives) were clearly better than students in the control group who were not instructed with manipulatives. (Contains 5 tables.)