On the Japanese Multiplication Method. A father-and-daughter dialogue

Abstract

Recently the media broadcast the news, together with illustrative videos, of a so-called Japanese method to perform multiplication by hand without using the multiplication tables. "Goodbye multiplication tables" was the headline of several websites, including important ones, where news are however too often `re-posted' uncritically. The easy numerical examples could induce naive internauts to believe that, in a short future, multiplications could be really done without the knowledge of multiplication tables. This is what a girl expresses, with great enthusiasm, to her father. The dialogues described here, although not real, are likely and have been inspired by this episode, being Maddalena the daughter of the author. Obviously the revolutionary value of the new method is easily disassembled, while its educational utility is highlighted to show (or remember) the reasoning on which the method learned in elementary school is based, although mostly applied mechanically.