Basic math question

[Stephen H]

By immediate profit they seem to mean that even if you lose all the times you're called, you'll *still* make money. The simple math they did:

X = percent of the time the BB folds and you win
1-X = percent of the time the BB doesn't fold and you lose.

$4 * X = avg amount per hand you win from the BB folding
$5 * (1-X) = avg amount per hand you lose from the BB not folding

Setting these equal to each other to find the value for X where EV = 0 gives you
4X = 5(1-X)
4X = 5 - 5X
9X = 5
X = 5/9 ~= .55

So there you go. Of course, this doesn't account for what might happen if the BB calls and you get post flop and start throwing bets around after that...but that's more complex blind steal/defense discussion.