re: Poker & do you call raises with small pairs?
Yeah, it is situational. You will play these in different ways based on table conditions and stacks and your read on the raiser/caller. In general, if there is a raise in front of you and noone has called, that is the worst case scenario for playing those. The ideal is when you have 3 or 4 limpers in front of you and you can enter cheap.
Looking at the example you made with a raiser and caller in front of you and you're in LP, I would fold anything like 55 and below and call with 7s and 6s only a certain percentage of times. The amount of that percentage is linked to table conditions, also if its a tourney it would depend on size of my stack, in certain situations I might go all-in even if there is a raiser and caller.
As for the question how many players need to be in the pot, if you can get in cheap I think 3 are enough (I may be wrong though) especially if they have nice stacks which give you great implied odds
. In that situation, particularly if its cheap, I'll call every time even with 22 and regardless of table conditions. One time in a tourney very 1st hand I did just that with 22 (I forgot how many were in the pot), hit a set on the flop and knocked out an unlucky player who made 2 pair on the river.