So, I'm a creating a spreadsheet which receives a number of inputs from the user and then does various calculations with these values. The user need only input 2 out of the 4 inputs below and as you can see, with 2 values, the other 2 can be calculated. How do I make it so that excel does this automatically? So, R = CP - CV (1) Gamma = CP/CV(2) CV = R/Gamma - 1 (3) CP = R + CV (4) I've inputted the above formulas into the relevant cells for R, Gamma, CV and CP (i.e. (1) into R's cell, (2) into Gamma's cell, (3) into CV's cell and (4) into CP's cell) but when I go and input R and Gamma, CV and CP aren't automatically calculated. I actually keep getting some error message about a circular reference.