What excel formulas should be used to get this answer?

Analysis:

a$.$ Create a monthly aggregation of sales data.

b$.$ Calculate the average price each month. Those months that you see a reduction in price are CLEARANCE months. Create an indicator variable equal to $1$ for clearance months and $0$ otherwise.

c$.$ Calculate the percentage returns of the different products by month. Make sure you account for the lags in the data! $($percentages should be entered either as $8\mathrm{.}38\%$ or as $0\mathrm{.}0838)$

d$.$ Calculate the percentage warranty exercises of the different products by month. Make sure you account for the lags in the data! $($percentages should be entered either as $8\mathrm{.}38\%$ or $0\mathrm{.}0838)$

e$.$ Analyze the monthly sales patterns of the different products.