Day, Today(), dtExpDate)) / 365 End Function End Module Notice that the TimeTillExp() function makes use of several functions we have looked at in this chapter, including Right() and Left() to find the second-to-last character in the option symbol string, DateValue() to convert a string representation of a date into a variable of data type Date, Year() to determine the year corresponding to the date returned by Today(), and DateDiff() to 102 Introduction to VB. We calculate the price of a call differently than we calculate the price of a put. A call option is a stock option. 35), take logs and substitute (5.