State tax filing
Most states start their tax calculations with the Federal AGI amount, so if you see this amount at the beginning of your state form, it's not unusual. They then adjust their calculations from there. You'll see this on the New Jersey Form 1040, with Column A showing the Federal Amount and Column B showing the NJ amount, and on the Income and Deductions Summary page in the NJ interview.
As you proceed through the state interviews, you get a chance to subtract various types of income that don't belong to that state, so pay close attention to the questions on each screen.
In New Jersey, look for a screen titled 'Did you earn all your wages in New Jersey?' where you can allocate the correct amount to NJ.
Here's more info on How to File a Non-Resident State Return.
