Arithmetic Teacher (1969) Vol. 16, No. 4

  • Arithmetic Teacher (1969) Vol. 16, No. 4

    An official journal of THE NATIONAL COUNCIL OF TEACHERS OF MATHEMATICS APRIL 1969 Volume 16, Number 4 Discovering patterns in addition George F. Edmonds Introduction to the numeration of two-place numbers Hitoshi Ikeda and Masue Ando Obtaining valid research in elementary school mathematics Dale P. Scannell The sorry s