Hi,as in message title, or more precisely I'm interested in approximation of asset price. Let's assume that one has function to price cash-or-nothing one touch digital option. So price of No Touch cash or nothing would be NoTouch = Payoff - OneTouchOption.And now let's consider a asset-or-nothing one touch digital option. If the payoff would be at maturity, then assuming situation of one as aboveNoTouch = S_0 exp(rT) - OneTouch.where S_0 is an asset price at time 0 and S_0 exp(rT) is a forward price of it. But I don't know now how it would be, if the payoff of an asset-or-nothing digital option is at the time, when the spot price hits the strike? We don't know neither the time of braking the strike nor asset price in that moment.In know I can be a very silly quastion, but I'm not familiar with option pricing very well.I'm looking for your answer people.rgds,Matt