In my spreadsheet I have two values which lead to a certain formula, the type
code and shape code to be specific. Like I said these values lead to a
formula, the formula itself refers to a set of cells in the same row with
values which are different per situation and need to be completed by the user.

Firstly how do I return a formula refering to column number (row number is
dependent on the row you are in.

Example for row 20
type code 8
shape code 15
Formula =P?? + Q?? - R?? * 8
(because we are in row 20 it becomes P20+Q20-R20*8)

Secondly:
Depending on the shape code (between 1-99) it determines how manny
additional values are needed for the formula, or formula itself
Can excel automatically shade the cells which need values?
For example Shape code 4 needs value A,B and C
Shape code 3 only needs value A
Shape code 92 needs value A,B,C,D and E


Thanks,

Willem