Calculating a Preflop Hand's Value

[Mikey]

In Small stakes Hold'em on pg. 49 in the footnote 22, there is this statement, "Gaining value and being profitable are distinct. If a hand is worth -$4, it can gain $3 of value and still be unprofitable."

Can someone explain to me this concept or guide me to where I can find information on calculating a hands value preflop.

The reason I ask this is because intuitively I believe I know when I can play a substandard or par hand when there are more players in the pot, but I would like to know more from a mathematical standpoint.

For instance there is a preflop raise UTG and 5 cold callers I called with 46s in the BB, but I wouldn't call that raise if the there was an UTG raise and 1 cold caller or 2 cold callers.

THanks in advance.

Mikey