It might surprised some that Calculator app in OS X comes with a paper tape feature. This feature is reminiscent of those old calculator with running paper tape, that keeps a running trail of each item entered. This is useful when you enter many items and needs to follow and audit the calculation.
To display the paper tape, select from Calculator app menu Window > Show Paper Tape, or press the keys Command-T. Use the same menu and shortcut keys to toggle and hide the paper tape window.
When you complete your calculations, save the paper tape trail into a file with menu File > Save Tape As. Or you can print out using menu File > Print Tape. Hit the “Clear” button to clean the paper tape and start over.