When playing we're against a range its more tricky to be sure on our outs, but its pretty quick and easy to guess in many circumstances and do the multiplication for the equity
The difficult bit for me is working out the pot and implied odds in % form. I don't have an easy trick for quickly working out how much additional money i'd need to make on river for a call to be +ev.
Edit; I have been prompted to make a short strategy post on my aforementioned short-comings, so without further ado;
Ingame Poker Math! Developing speed tricks.
The Scenario
You may have had the following situation before in game; You flop a good hand like a set or TPTK Cbet and get called, on the turn you bet and get check-raised.
The easy part is working out your outs. With a set your villain check/raised a completed flush on turn and with TPTK the board is dry and he Check/raised a two-pair. Set has up to 10 outs for FH/Quads i.e 22% and TPTK has up to 6 clean outs, possibly 3 extra unknown outs. This is 13% (or 19%)
Now however, despite knowing this you hit a roadblock. "I have 22% equity and bet 5 into 7.5, he raised to 15 and has 28 behind but might not put his whole stack in every time, so can I call or not?"
This was my somewhat panicked thought process which then progresses on to the following;
"7.5 + 15 + 5 = 27.5 and I have to call 10? thats about a third of the new pot? I don't have that equity but if he puts his stack in on river only some of the time I have the implieds to call don't I!"
This in-accurate thought process can be sufficient in some cases where it becomes apparent very quickly that we have the implieds to call, but its not exactly confidence inspiring. Having presented the problem I shall try and lay out the quick math shortcuts to use in the game to make things easier and more accurate.
The Solution
What things would we like to be able to calculate quickly and easily?
- Pot Odds in Numbers and Percentage terms
- Our implied pot odds in Numbers and Percent terms
- The amount villain has to put into the pot on river on average to make our call +ev
1) Pot Odds
We bet 10 into a 15 pot and villain raises to 30.
Pot = Villains raise+ original pot + Our bet = 30 + 15 + 10 = 55
We have to call 20 into 55 but what is the quickest and easiest way to phrase this in pot odds and as a percent?
Thought A: 20 : 55 is almost the same as 2:6 which is 1:3
Is this accurate enough? We could get more accurate but we won't have time in game.
Thought B: To express 1:3 as a percent we can do the following;
Left hand side / (left + right) = fraction we can hopefully convert into a percent.
1 / 4 = 25%
Accuracy test, real result = 26.7%
This looks like it will help a lot more, lets recap the steps.
1: Add up pot so you can work out how much you are calling to be a part of.
2: Try to express "Amount to call : Pot" into a simple ratio.
3: Get a fraction to approximate a percent with the formula "Left hand side / (Left + Right sides)"
2) Implied pot odds
We should be able to use the same process we used for pot odds just adding either entire effective stack behind if we think villain goes all in every river, or a percent of effective behind eg 50% if we think he only goes all-in half the time on river.
eg; we bet 22 into 30, villain raises to 90. His remaining is 200 and ours is 250.
1: 90 - 22 = 68 to call. Pot = 22 + 30 + 90 = 142. We guess we get 100 extra per average hit so we call 68 to win 242.
2: 68 : 242 -> 70 : 240 -> 7 : 24 -> 3.5 :12
3: 3.5/15.5 aproximately 4/16 = 1/4 so 25% effective implied odds.
Accuracy test. Real result = 22%
This one definitely took me way to long to do quickly in-game and I didn't feel it was very accurate. That said I did deliberately try and find obtuse numbers to work with because that's always the way it happens in-game.
3) The amount villain has to put into the pot on river on average to make our call +ev
This is the number I would absolutely love to have time and time again whilst playing poker, but how can we possibly work it out quickly and easily?
Here is my idea;
1) Take our equity % and round it to the closest easy to use multiple of ten, 5 or 2.
2) Take the figure we have to call and divide by this number to find the value of 1% of a pot that would be break/even for us.
3) Multiply this figure by 100, to find the break/even pot size for this call.
4) If this figure is larger than current pot-size find the difference between the two to see how much we need to make on river when we hit. (If figure is smaller we already have a +ev call)
Or "Required riverbet size = [(amount to call / equity)*equity]- Potsize"
Lets test;
We have 22% equity, we bet 10 into a 15 pot and villain raised to 40.
1: 22% is difficult, lets use 20%.
2: We have to call 30, 30 divided by 20 is 3/2 = 1.5
3: 1.5 * 100 = 150
4: Potsize is 65 so we need to make 150 - 65 = 85 on river when we hit.
That seems like a lot so lets see if I got my sums right; Our implied odds calling 30 here if we get 85 when we hit are 30:85+40+15+10 = 30:150
30:150 in % will be the fraction 30/180 = 16.6%
Ok, not sure where I went wrong. I shall revisit this later to correct myself. Off on holiday for two nights! GL at the tables
edit; Revisiting to do some implieds examples;
1) We bet 3/4 pot, villain 3xs our bet. How much do we need to make with, 10%, 20%, 25% 30%, 40% equities?
Pot 100, we bet 75, villain raises to 225.
10% equity -> (150/10)*100 - 400 = 1100 or 2.75 * current potsize before calling.
edit: 15% equity -> 600 or 1.5*currrent potsize before we call.
20% equity -> (150/20)*100 - 400 = 350 or 87.5% of current potsize before calling.
25% equity -> (150/25)*100 - 400 = 200 or 50% of current potsize before calling.
30% equity -> (150/30)*100 - 400 = 100 or 25% of current potsize
40% equity -> (150/40)*100 - 400 = -25 - implieds not needed.
2) We bet 3/4 pot, villain 4xs our bet. How much do we need to make with the various equities?
Pot is 100, we bet 75, villain raises to 300
10% -> (225/10)*100 - 475 = 1775 or 3.7 * current pot before calling.
20% -> 650 or 1.36 * current pot before calling.
25% -> 425 or 89% of current pot before calling.
30% -> 275 or 58% of current pot before calling.
40% -> 87.5 or 18% of current pot before calling.
Seeing those figures is quite interesting I think. If we bet potsize we need to make more on river when we call, if we bet less then we need to make less. With these examples we can see the sweet spot equity wise that implieds primarily concern.