Work

The 84% Method: A Terminal-Digit Selection Heuristic for Two-Digit Mental Multiplication

Year: 2026

Type: preprint

Abstract: The 84% Method is a selection heuristic for two-digit mental multiplication. It classifies a factor as favorable when its units digit is 0, 1, 2, 5, 8, or 9. Under uniformly distributed terminal digits, the probability that at least one of two factors is favorable is 1 − (4/10)² = 84%. The 84% figure refers to the coverage of the selection criterion, not to a measured speed improvement.

Source: Zenodo (CERN European Organization for Nuclear Research)

DOI: 10.5281/zenodo.22336975

Author: Roder, Timon Felice Amand

Institution: University of Tübingen

Language: English

Topic: Cognitive and developmental aspects of mathematical skills

Subfield: Statistics and Probability

Field: Mathematics

Domain: Physical Sciences

Open Access status: green

OpenAlex ID: W7208821273

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