Get your taxes done using TurboTax

I'm old-please help me.  So, if I take the Total Income and subtract the Federal Deductions is that my AGI?  Or do I also subtract the taxable income too? to get the IRS the answer they want.  My 2019 tax forms were re-jected .  They want to know my AGI for 2018.  I use Turbo Tax.  Is the number Turbo Tax has printed in blue on the correct or is that a "test" by the IRS?