Instruction and study (1) Counting (1) Employment (1) Propagation (1) Textbooks (1) Tables (1) Textbooks (1) Male primary school teachers (1) Primary school teachers (1) Male elementary school teachers (1) Worms (1) Sports records (1) Preschool teachers (1) Numerals (1) Necessity (Philosophy) (1) Interns (1) International division of labor (1) Example (1) Elementary school teachers (1) Counting (1) Athletic ability (1) Mental arithmetic (1) Addition (1) Women preschool teachers (1) Mathematics (1) Study and teaching (1) Practice (1) Occupations (1) Students (1) Cálculo mental (1)