the decimal point

The zero and the counting numbers (1,2,3,...) make up the set of whole numbers. But not every number is a whole number. Our decimal system lets us write numbers of all types and sizes, using a clever symbol called the decimal point.

As you move right from the decimal point, each place value is divided by 10.




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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 .