On Feb 27, 10:36 am, Mary wrote:
Please help Why 28E50 changes to 2.80E+51. I tried to format them as text and
does not work.

Well, you would need to format the cell __before__ entering the
string. Most of us are not blessed with such foresight.

Alternatively, enter '28E50 -- that is, an apostrophe before 28E50.
Excel will not display the apostrophe. It simply tells Excel not to
interpret the text as a number.