I have three fields in customer invoice form "Current reading(cr)" ,"Previous reading(pr)" ,"Free copies(fc)" , The three columns have values . Default value of Unit price is 0.15 Paise
cr=3000, pr=1000 , fc= 1000 unitprice="0.15"
((cr - pr)-(fc))*unit price of my product. = ((3000-1000)-(1000) * 0.15
I want to display 150 in my unit price field in customer invoice.
How can be make this.
Thanks in advance.