The document discusses the structure of the school system in Mexico and Spain. In Mexico, primary school consists of 6 grades from ages 6 to 11, secondary education lasts 4 years from ages 12 to 16, and 6th form lasts 2-3 years to prepare for higher education. In Spain, primary school has 6 levels from ages 6 to 12, secondary education has 4 levels plus 6th form to prepare for university. The school year is divided into semesters in Mexico and trimesters in Spain.