The value on line 8b is approximately the sum of:
Box 8 on all your 1099-INT forms
Plus
Box 10 on all your 1099-DIV forms
Edit those and see if you double-entered one of the forms, but maybe it's just that you didn't realize it included both of them.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
