How to calculate real wage?

Nominal Wages(W) (Link: https://fred.stlouisfed.org/data/AHETPI.txt)Price index CPI(P) (Link: https://fred.stlouisfed.org/data/CPIAUCSL.txt)

Let us go back to the 1981 - 1982 recession - review the NBER site Note that officially, this recession began in third quarter of 1981 and ended in the fourth quarter of 1982.

a)Calculate the real wage (W/P) the first month of the recession 7/81 and compare it to the last month of the recession 11/82. What is the percent change in the real wage during this most recent recession?

b) Calculate the real wage during the first month of the recovery, 12/82 and compare it to the real wage right before the following recession, 6/90. What is the percent change in the real wage during this time period?