I understand the concept, but I don't really see how to figure out if a situation is +EV or -EV in play. I know pot odds cold.

I'll see if I can give an example..

Let's say I'm MP2 with JTs. I call .10 bb to limp in, and then SB goes allin with his whole stack of $1.25. Is calling this raise a +EV with my hand?

Another one..

Suppose I have 67s, against a possible AA KK or AK due to two reraises preflop, and I call. 4 8 2 hits the flop. The pot is $4.25 and the AA bets $3. Terrible pot odds for me, but is calling a +EV?

Is it ever -EV to push a straight or flush on the river if you miss it on the turn?

I would love to get this concept down. Jackvance you seem the brightest on this board, would love to hear from you on this as well.

EDIT: I read another scenario on another thread that I should always be calling 4xbb raises with pocket pairs (22 33 44 55 66 etc.) because it's +EV. Well I've been doing that and it seems I'm just throwing my money away because I never hit on the flop. How is this +EV? Is it still +EV if the 4xbb gets raised preflop? I