We are on a holy mission in the name of the poker gawds to discover the lost and secret art of quantifying fold equity. Seeking math wizards and numerological mages who have reached enlightenment in these arts.

I am using the formula

EV = P(f) + (1-f)[EV(P+R+R) - S]

this has the same result as

EV = P(f) + (1-f)[EV(P+R) + (1-EV)(-S)]

and we are trying to find the value for f (fold equity) where EV = 0 or break even.

The following once in a lifetime scenario plays down at a poker table in some obscure and secret underground location.

BB posts 400,

SB posts 200,

pot 600,

Action folds down to BU

BU raises 800,

pot 1400,

SB raises 800 all-in,

pot 2800,

BB folds,

BU calls 800 (maybe or maybe not),

pot 3600

At some point the SB collected the following variables and proceeded to do a most simple mathematical calculation.

Pot if fold (P) = 1400 (3.5BB)

Stack if lost (S) = 1400 (3.5BB)

Raise (R) = 800 (2BB)

EV = 56.09 (66 vs K8o)

= P(f) + (1-f)[EV(P+R+R) - S]

= 1400f + (1-f)[0.5609(1400+800+800) - 1400]

= 1400f + (1-f)[0.5609(3600) - 1400]

= 1400f + (1-f)[2019.24-1400]

= 1400f + (1-f)619.24

= 1400f + 619.24 - 619.24f

f = -619.24 / (1400 - 619.24)

f = -619.24 / 780.76

f = -79%

Eureka we have found the answer, fold equity is -79%. BOOM!

Keeping his best poker face to not reveal any

tells of his complete and utter confusion the SB quickly runs the calculation again, from a less than ideal spot this time.

EV = 25%

= P(f) + (1-f)[EV(P+R+R) -S]

= 1400f + (1-f)[0.25(1400+800+800) -1400]

= 1400f + (1-f)[0.25(3600) -1400]

= 1400f + (1-f)[900-1400]

= 1400f + (1-f)-500

= 1400f - 500 + 500f

f = 500 / (1400 + 500)

f = 500 / 1900

f = 26%

Snap! Dude on BU you should fold 1:4 times for us to break even, who's your daddy. But the BU called and he watches his chips get shipped away...

Now, the question of the universe and everything can anyone PLEASE tell me what on earth -79% is supposed to mean?