Arithmetic Teacher (1972) Vol. 19, No. 3

  • Arithmetic Teacher (1972) Vol. 19, No. 3

    An officfal journal of THE NATIONAL COUNCIL OF TEACHERS OF MATHEMATICS MARCH 1972 Volume 19, Number 3 The concept of the shifting unit A.lfred Ellison A number is a set of • • • ? NO!! Larry Sowder The addition table: Experiences in practice-discovery MargtUet A. Hervey and Bonnit H. Litwiller Gus's magic numbers: A ke