mathematicians suck at parentheses

it's true

Really, when I see in a math book

D = -N . P   [D is a scalar, N and P are vectors]

...is it -(N . P), or ((-N) . P)?

Of course, I'm too lazy to check, but those may or may not be equivalent.

Is it that hard for mathematicians to use parentheses to clarify things a bit?

wouldn't it be [(-N) . P] because the P vector isn't negative, only the N?