i have to create a number from a 18 digit number the math is simple and so is getting the result this is how i do it
i have a 18 digit number like this
982613530890001448
then i split the number like this using the text to columns command in excel
so i get this result in many columns
9 8 2 6 1 3 5 3 0 8 9 0 0 0 1 4 4 8
then i have to multiply every second number by 2 like this
8*2 6*2 3*2 3*2 8*2 0*2 0*2 4*2 8*2
this gives me this result
16 12 6 6 16 0 0 8 16
then i split each one these numbers into two like this
1 6 1 2 6 6 1 6 0 0 8 1 6
then i add all these numbers together and the remaining numbers that havent been doubled together to get a figure like 76 then round up to nearest ten then subtract 76 from 80 to get my final figure then i have a nineteendigit number like this
9826135308900014485 4
this is the number i need i can do it in one field using data i input but how can i doit over multiple fields so that i can copy the last seven digits from a excel spreadsheet into this one and create a list of numbers including the last figure using my unique formula

please help me