it may be easiest to review your tax return transcript even download it. it shows amounts per return and what the IRS computers say the numbers should be. this can be done online
https://www.irs.gov/individuals/get-transcript
or by using the online link (or filing form 4506-T) you'll get a copy of the transcript through the mail
online
https://sa.www4.irs.gov/irfof-tra/login
mail form 4506-t
https://www.irs.gov/pub/irs-pdf/f4506t.pdf
