Castro Hernández, Carlos DeCastro Martínez, EnriqueSegovia Álex, Isidoro2023-06-202023-06-2020020-9539983-6-3https://hdl.handle.net/20.500.14352/60521In this study we analyze the difficulty of computational estimation tasks –with operations without context– in function of the operation type –multiplication and division– and number type –whole, decimal greater than one and decimal less than one– that appears in them. Errors made in estimating with decimal numbers less than one are also analyzed. The research counts with the participation of 53 preservice elementary teachers. An estimation test is administered to the teachers and some of them are selected to accomplish interviews. The conclusion is that estimating with decimals less than one is more difficult than with whole numbers or decimals greater than one, and most of the errors –but not all– produced in estimation processes is due to teachers’ misconceptions about operations of multiplication and division.engbook partopen access37.02 Didáctica y metodología.51 Matemáticas.Mathematics EducationComputational EstimationDecimalsErrorsTeacher EducationEducación MatemáticaEstimación en cálculoDecimalesErroresFormación de MaestrosEnseñanza de las Matemáticas