Computational estimation for numeracy

The importance of computational estimation is generally acknowledged. The widespread introduction of the hand-held calculator greatly increases its significance, particularly as a means of teaching number sense.The reason for its failure to be taught is traced to the multiplicity of methods used in estimation. Some agreed procedures are therefore suggested. These procedures have been developed in an unusual situation but are appropriate elsewhere. Detailed suggestions are made for estimating sums, differences, means, products, quotients and percentages.