In the American system, one billion equals 
. In the French and German systems, one billion
equals 
.
In recent years, the "American" system has become common in both the United States and Britain. In the words of The Chicago Manual of Style (2003), "The American definitions are gaining acceptance, but writers need to remember the historical geographic distinctions." This use of a common meaning for "billion" constitutes a fortunate development for standardization of terminology, albeit a somewhat regrettable development from the point of view that the British convention for representing large numbers is simpler and more logical than the American one.
See also
Large Number, Milliard, Million, Trillion
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References
The Chicago Manual of Style, 15th ed. Chicago, IL: University of Chicago Press, pp. 203 and 382, 2003.
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Cite this as:
Weisstein, Eric W. "Billion." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Billion.html