The hypothesis was tested that students with a field-independent cognitive style would learn most about numeration systems if they had minimum guidance and maximum opportunity for discovery through the use of manipulative materials. Data were gathered on 46 prospective elementary school teachers. The hypothesis was supported. (Author/MH)

Preservice elementary teachers enrolled in a mathematics course were randomly assigned to one of two treatment groups for instruction on computation in bases other than 10. Group 1 (Min-M) involved minimal guidance and a concrete level of abstraction, while group 2 (Max-S) had a large amount of guidance and dealt with concepts at a symbolic level.…