Now I know I made a mistake on Form1040, 18e, how can I go back and change it?

[Critter-3]

Line 18e is a total of lines 18a thru d ... which line is incorrect ?   And have you filed yet ?  

[DoninGA]

Form 1040 Line 18e is the sum of Lines 18a thru 18d.  

Line 18a is calculated by the program, based on your entries for the Earned Income Tax Credit.

Line 18b is calculated by the program based on the dependents you entered and the income you entered.

Line 18c is calculated by the program based on what you entered for your education expenses and your income.

Line 18d is from Schedule 3, Line 14. 

What exactly do you need to change on your tax return?

Review your return -

Click on Tax Tools on the left side of the screen. Click on Tools. Click on View Tax Summary. Click on Preview my 1040 on the left side of the screen.