The purposes of this study were to investigate the effects of Cooperative Learning on mathematic achievement, problem-solving process and peer-interaction of low-achieving students in the area of mathematics. The students involved were 56 average and 6 low-achieving students from two regular classes in the Jian-Gunges Elementary School in Miaoli County. One of the class attended Cooperative Learning arrangement, the other was control group. Low-achieving students were three in each class. Topic of Instruction in both classes were plane geometry units from regular classes mathematic curriculum
