This document discusses the use of didactic materials in teaching mathematics in Portuguese elementary schools. It provides background on the school being studied, which has 514 students in 22 classes. It then discusses the importance of using materials to help students concretize mathematical concepts. The rest of the document analyzes survey results from 53 teachers at the school on their use of different materials, including calculators, computers, and textbooks. It also discusses the role of Portugal's Technological Plan in providing materials like laptops and interactive whiteboards in classrooms.