SCIENCE FILE : I Didn’t Know That ...

Q: Why does the United States use a period as a decimal point while so many other countries use a comma?

A: The need for a symbol to separate fractions from whole numbers, called a decimal separatrix, has been recognized since at least the 15th century. The character used for the symbol is completely arbitrary and, over the years, mathematicians have used single lines, double lines, bars, semicolons, dots on top of numbers and circles beneath them. By the 18th century, the race came down to the dot and the comma, with England using the dot and the continental countries largely using the comma. British mathematicians eventually decided that the dot should be reserved for use to signify multiplication and boarded the comma bandwagon. Although the comma was widely used in the United States because of French influence, an American standardization committee early this century settled on the period.