Please help me with my homework. I need to do the calculations in Excel to find the answer, and I don't know how

Physician office revenue for visit code 99214 has a full established rate of $75.00. Of 5 different payers, there are 5 different contracted rates, as indicated in the template provided. For each payer, compute the contractual allowance using the template provided

\begin{tabular}{|l|r|r|r|} \hline COLUMN & A & B & C=A-B \\ \hline PAYER & FULLRATE & CONTRACTEDRATE & CONTRACTUALALLOWANCE \\ \hline FHP & $75.00 & $35.56 & \\ \hline HPHP & $75.00 & $54.68 & \\ \hline MC & $75.00 & $45.19 & \\ \hline UND & $75.00 & $23.40 & \\ \hline CCN & $75.00 & $37.82 & \\ \hline \end{tabular}