[1] Both formats break a number down into a sign bit s, an exponent q (between qmin and qmax), and a p-digit significand c (between 0 and 10p−1).
Using the fact that 210 = 1024 is only slightly more than 103 = 1000, 3n-digit decimal numbers can be efficiently packed into 10n binary bits.
However, the IEEE formats have significands of 3n+1 digits, which would generally require 10n+4 binary bits to represent.
The Decimal64 and Decimal128 encodings have larger exponent and significand fields, but operate in a similar fashion.
A binary encoding is inherently less efficient for conversions to or from decimal-encoded data, such as strings (ASCII, Unicode, etc.)