For long arithmetic equations, I typically do one of two things.
leave everything on a single line:
foo = bar + baz - fizz + buzz + alpha - beta;
I typically do this for equations containing only addition and subtraction, i find it very easy to make a typo with multiplication and division that can seriously mess up the scope of the operator.
the second format I use is progressive operators:
foo = bar;
foo += baz;
foo -= fizz;
foo += buzz;
foo /= alpha - beta;
foo *= spiff;
I see no reason to shorten it to a single line, unless it can be proven to improve performance in a noticeable manner. Additionally, there's no ambiguity of what's going on where, and there's less of a chance to misplace a parenthesis for the