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., ), 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., , is equivalent to moving a decimal point
digits to the right, and dividing by
is equivalent to moving a decimal point
digits to the left. So, for example,
, while
.
Similarly, multiplying by a power of , i.e.,
, in base
is equivalent to moving the "
-ary point"
digits to the right. For example, in binary (
),
, so
.