On my 1099-int form it has 3 different accounts should I add the all together

Yes, you can add the amounts if it's the same payer (bank). Note: All income, such as interest under $10 is taxable unless the law specifically excludes it. For additional information, click on Taxable and Nontaxable Income | Internal Revenue Service - IRS.gov

You can also enter each account separately. It's your choice. See Where do I enter Form 1099-INT?