How is total federal tax provision calculated and effective tax rate calculated?

Pre-Tax Net Income 1,915 1,335 425 Federal Income tax expense NOL carryforward from PY NET INCOME 75 (75) (75) 1,490 1,260 21% 265 Federal Tax Rate Federal Income Tax Liability Total temporary differences Deferred tax Asset/Liability Total Federal Tax provision (765) 161 Effective Tax Rate