Im having trouble understanding how to get the last column (CFAT) for part b

this is all that is given

Depreciation Effects on Taxes Complete the last four columns of the table below using an effective tax rate of 40% for an asset that has a first cost of $20,000, no salvage value, and a 3-year recovery period. Use (a) straight line depreciation, and (b) MACRS depreciation. (All cash flows are in $1000 units.) Estimates, $ Year GI POE D TI T CFAT -20 -20 2 15 _-___ 3 12 03__ 4 10 0-5___