PPupil's arithmetical ability: differences due to the teacherPupil's arithmetical ability: differences due to the teacherde Toivo VahervuoMateriasArithmeticStudy and teachingEdiciones (1)Pupil's arithmetical ability: differences due to the teacher (1957)inglésMás obras de Toivo VahervuoTThe awarding of school marksThe awarding of school marks1958PPupils' arithmetical abilityPupils' arithmetical ability1957TTutkimuksia keskikoululaisten matemaattisesta suorituskyvyst