Wait until calculator button appears. Sometimes You Need To Press Refresh
Graphical Representation of Option Price and Sensitivities
Lionel MacMillan orginally suggested valuing options using a quadratic approximation approach in 1986.
The approach was implemented by
Giovanni Barone-Adesi and Robert Whaley in 1987.
This approach has been used to value American calls and puts on stocks, stock indices, currencies and future contracts. The mathematics of their derviation is quite complex. Interested readers can find it in the original paper, MacMillan Barone Adesi and Whaley (1987), and the books by Hull (1993).