Did he do the calculations in his head? Where's the line where it's OK
for your contractors to pull out a calculator?

For me, it is when they are shooting a price out there without a detailed
proposal. I'm good at math, but I do occasionally make mistakes. To me,
it's about the same as a guy pulling out a measuring tape instead of saying,
12 feet by 39 feet at $8.17 per square foot material, plus $3.50 per man
hour labor, plus taxes and permit fees, which comes to around
..................... un ......... uh ........... $8,000. Will that be cash
or check?

I see it as a sign of a professional, unless the job is very obvious, like
my welded gates. I could shoot a total price, no need of itemizing them.
Now, if that is plus a run of fence, I'd do a calculation, and either way,
it goes on paper as a written proposal, a necessity in the offer/acceptance
sequence of real contracting. Once they sign it, and pay the deposit, it is
a contract.

Steve