how do I go back to a spreadsheet in numbers after making a current mistake?

HI murph.

It depends on how big the mistake was.

If you only entered a wrong value in a single cell, just replace that value with the correct one.

If you entered a value in a cell that originally contained a formula, then

• if the formula was created by filling an original formula up or down a column, or by filling an original formula left or right in a row, click on an adjacent cell, and use the fill handle (small yellow circle) to drag and copy the formula into the target cell.
• If the formula is a standalone formula, double click the cell to open the formula editor, and rewrite the formula.

Beyond those situations, use Revert, as suggested by Peggy. Even given those simple situations, you may find Revert to be a more efficient method.

Regards,

Barry

Go File > Revert To then choose one of the options

You're very welcome.