Lay, L. Clark.
The study of arithmetic / L. Clark Lay. - New York : Macmillan, c1966. - xv, 590 p.
66-23918
Arithmetic--Study and teaching (Elementary).
Arithmetic--Study and teaching (Secondary).
Mathematics--Study and teaching (ELementary).
Mathematics--Study and teaching (Secondary).
The study of arithmetic / L. Clark Lay. - New York : Macmillan, c1966. - xv, 590 p.
66-23918
Arithmetic--Study and teaching (Elementary).
Arithmetic--Study and teaching (Secondary).
Mathematics--Study and teaching (ELementary).
Mathematics--Study and teaching (Secondary).