State tax deduction

My Schedule A, line 5a shows a deduction for State and local income taxes but I had none withheld during the year. The number on line 5a is very different from the state tax I paid with my 2018 return and the estimated state tax payments I made during the year. Where does this number come from (the worksheet is no help)?

posted

Sorry - finally figured it out. It reflects only the estimated tax payments for the first three "quarters" of 2018 because those were paid in 2018. Then fourth quarter payment was made in January 2019. Duh!