Cannot center a bar (macron) accent on top of character.

I am trying to accent a number with a bar (macron?) on top, using strictly the Insert Symbol option. I have read instructions and watched a number of YT videos that successfully do that. But when I follow the instructions, the bar is not centered on top of the character, but always skewed to its right like a superscript. There are already bar-accented letters in the symbols list, but those are not useful to me because I am trying to insert the bar on top of a number, not a letter. I also tried inserting the bar through the Alt+code option, but the bar remains to the right of the number.