#### 16.4.1 Floating-Point Arithmetic Is Not Exact ¶

Binary floating-point representations and arithmetic are inexact.
Simple values like 0.1 cannot be precisely represented using
binary floating-point numbers, and the limited precision of
floating-point numbers means that slight changes in
the order of operations or the precision of intermediate storage
can change the result. To make matters worse, with arbitrary-precision
floating-point arithmetic, you can set the precision before starting a
computation, but then you cannot be sure of the number of significant
decimal places in the final result.