Question

From MSDN:

A decimal number is a signed,
fixed-point value consisting of an
integral part and an optional
fractional part. The integral and
fractional parts consist of a series
of digits that range from zero to nine
(0 to 9), separated by a decimal point
symbol.

I thought it was a floating point number with base 10.

Answer 1

If you change the version of the Framework the description changes:

With 4.0

A decimal number is a floating-point
value that consists of a sign, a
numeric value where each digit in the
value ranges from 0 to 9, and a
scaling factor that indicates the
position of a floating decimal point
that separates the integral and
fractional parts of the numeric value.

I’ll say it’s sloppy editing of the 1.1 version.

And even in 1.1 in the next paragraph it’s written:

The binary representation of an
instance of Decimal consists of a
1-bit sign, a 96-bit integer number,
and a scaling factor used to divide
the 96-bit integer and specify what
portion of it is a decimal fraction.
The scaling factor is implicitly the
number 10, raised to an exponent
ranging from 0 to 28.