math for hands against you

Most of the reading material on poker odds have to do with the possibility of you getting a certain target hand based on what you are holding. For instance, what are the chances of you getting a straight if you have three consecutive ranks. But equally important I would say, are the odds of someone else getting a hand that could beat yours. For example, let's say you have pocket aces. But the flop shows 7 8 9. And there are four players. what are the odds that one of your opponents now has a straight? Of course it would also depend on how many players. Is there any place to go where I can find a listing of odds like these? Is there even a word for it like counter-odds?

The word commonly used is your equity (chance of winning) in the hand.

How many hands connect with 789
56 - 16
6T - 16 but that should pretty much never play
TJ - 16
If they are only playing suited connectors then 4 each for 8

77, 88, 99, 78, 79, 89 also has you beat

In early to mid position only 77, 88, 99 would open.
Mid suited connectors might open, call, or raise from middle to late.

There are about 1000 starting hands but only like 300 are played.
You are behind like 38 hands. `1 - ((1 - 38/300)^3) = 33%`

You should not be seeing a flop against 3 with AA. You need to price this type of hand out pre flop with AA. First in a raise. Re-raise. If 3 bet jam.

There are many equity calculators out there for this type of stuff. Equilab has a good free one.

If you dont want to do the math yourself, there is a quicker and easier way to calculate odds and probablity. Use propokertools.com, it is a great site. Not only can you calculate one hand versus another. But also one hand versus a certain range of hands. Just put in your hand, the board and the range you expect your opponent(s) to have and you can calculate your odds.