How should Mary report the total interest earned from her three savings accounts?

Mary should report the total interest earned from her three savings accounts on Schedule B. Schedule B is specifically designed for reporting interest and dividend income, allowing taxpayers to list all sources of interest income over a certain threshold. By completing this schedule, Mary can provide the IRS with a detailed account of her interest earnings, which are included in her total income on Form 1040.

This approach ensures compliance with IRS regulations, as it helps to distinguish between various types of income. While the total interest income derived from her savings accounts will ultimately flow to Form 1040, the necessary details and calculations are first outlined in Schedule B. This method also helps facilitate any potential further inquiry or verification by the IRS regarding the sources and amounts of interest reported.