Effectiveness of Systematic Instruction on Attitudes and Computational Estimation Skills of Preservice Elementary Teachers.

Estimation involving mental computation is a very important skill. Recent recommendations on basic mathematical skills have included estimation as a fundamental skill that every student should develop (Bell, 1974; National Council of Supervisors of Mathematics, 1977; National Institute of Education, 1975). In fact, estimation is more important and practical than precise calculation for many everyday uses of mathematics. The widespread use and availability of hand calculators places additional importance on computational estimation skills to ensure the user that values displayed on the calculator are reasonable. Despite its importance, estimation is perhaps the most neglected skill in the mathematics curriculum (Carpenter, Coburn, Reys, & Wilson, 1976). The cursory treatment given to estimation in most mathematics programs is insufficient to build any appreciable estimation skills. Computational estimation is traditionally introduced around the fourth grade. It frequently appears as a separate topic that is poorly motivated and subsequently ignored with the return to traditional calculation problems. The lack of attention to computational estimation is reflected in the low performance of all age groups in the first National Assessment of Educational Progress (Carpenter et al., 1976). These performances were consistent with those reported earlier by the National Longitudinal Study of Mathematics Ability (Wilson, Cahen, & Begle, 1968). A review of basal mathematics textbooks (Skvarcius, 1973) as well as content and methods textbooks for elementary school teachers shows that very little attention is given to the systematic development of computational estimation skills. Trafton (1978) expressed a hope shared by these researchers that "more will be learned in the next few years about how students develop these skills, how this work can best be integrated into the curriculum,