How to add a number of days from an inputed date?

[Henry.Ong]

I have three fields in my PDF form.

1st Field : CurrentDate (format date)

2nd Field : Number of Days (format numeric)

3rd Field : ExpiryDate (format date)

What I would like to happen is when I input a date in CurrentDate, the ExpiryDate will be computed using the formula below:

ExpiryDate = CurrentDate + Number of Days

Thanks in advance.