well, p + (-2), now a sign in front of a grouping symbol usually means it has a 1*, so +(, really means +1*, thus p + (-2) really means p + 1*(-2), which gives us p - 2, and that'd be ordinally, 2 numbers to the left of "p".
likewise, 5 + p, is just the same as p + 5, so that value will be a number 5 numbers to the right of "p".
just as above, p + 1, is just one value to the right of "p".