"joeu2004" wrote...
....
Addition needs care to avoid rounding/truncation or spurious precision
errors. Multiplication usually doesn't

I disagree. Multiplication of fractional digits is more likely to
give the false impression of greater precision. In the example, 10.1
* 9.01 ostensibly results in a number with 3 decimal places (91.001).
The science text that I referred to would have us round that result at
least to 2 decimal places, but probably to 1 decimal places.
....

With multiplication you can defer rounding until the final result. And you'd
better defer rounding when dealing with compound interest. Addition, on the
other hand, begins to suffer as soon as you 'combine' numbers at different
orders of magnitude.