1. The problem statement, all variables and given/known data using the table of values supplied (a pdf document), construct an excel spreadsheet wherein a value can be input from 200-2250 and output will be air's specific heat capacity at that temperature. 2. Relevant equations Cp= H2-H1/T2-T1 3. The attempt at a solution I have completed most things, I am just having issue where an exact value is entered on the temperature table, ie 200 has a value for H, and as such my formula input in both cells which is designed to essentially round down or up from the value selects the same values for Temperature and thus divides by zero. I am currently attempting to input an If statement into the cell containing the upper (T2) value, but containing too many arguments. This is the statement i have been using to calculate temperature for the upper: =SMALL($D$18:$D$138,COUNTIF($D$18:$D$138,"<"&M21)+1) inputting an if function I thought of but it ended up containing too many arguments (essentially if A1=A2 then above formula acts as if M21 was added with +1 to its cell). So is there a way to simplify? Or should i make cell 2 conditional upon cell 1 and try and make it select the next sequential cell automatically? How do I do that? Any and all help is appreciated.