The article presents the design and validation of an instrument about the "knowledge for teaching numbers in prospective childhood teachers". The instrument has three theoretical components relating to teacher knowledge: i) logical mathematical concepts associated with number construction, ii) teaching organization, and iii) learning stages about logic and number. The instrument proposes two classroom situations about childhood education to evoke teacher knowledge. The results show that the instrument has content validity and construct validity. It has internal consistency of 0.72. The article concludes that the instrument can be useful in teacher education programs in early childhood education.
Childhood education; Teacher training; Mathematics education.