If these are numbers simply formatted with a single decimal to the
right of the decimal point, then the '.0' is only part of the cell's
display, not it's value or formula. Excel's Edit Find can only
search through cells' values or formulas, not what they display.

Not exactly. If you show all the options (using the Options button if
necessary), type .0 (that is dot-zero) in the "Find what:" field, click the
Format button and select the same format that the cells are formatted to,
and select Values in the "Look in:" drop down, then the Find All button will
locate all the cells ending in .0 (dot-zero).

Rick