Decimal Point

The symbol used to separate the integer part of a decimal number from its fractional part is called the decimal point. In the United States, the decimal point is denoted with a period (e.g., 3.1415), whereas a raised period is used in Britain (e.g., 3·1415), and a decimal comma is used in continental Europe (e.g., 3,1415). The number 3.1415 is voiced "three point one four one five," while in continental Europe, 3,1415 would be voiced "three comma one four one five."

Multiplying by a power of 10, i.e., 10^n, is equivalent to moving a decimal point n digits to the right, and dividing by 10^n is equivalent to moving a decimal point n digits to the left. So, for example, 1.2345×100=123.45, while 1.2345/100=0.012345.

Similarly, multiplying by a power of b, i.e., b^n, in base b is equivalent to moving the "b-ary point" n digits to the right. For example, in binary (b=2), 5.5_(10)=101.1_2, so 2×5.5_(10)=1011.0_2.

See also

Comma, Decimal, Decimal Comma, Decimal Expansion

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Wells, D. The Penguin Dictionary of Curious and Interesting Numbers. Middlesex, England: Penguin Books, p. 80, 1986.

Referenced on Wolfram|Alpha

Decimal Point

Cite this as:

Weisstein, Eric W. "Decimal Point." From MathWorld--A Wolfram Web Resource.

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