Most common reason is the cells are pre-formatted as Text.

Select a "bad" cell and F2 and ENTER


Gord Dibben MS Excel MVP

On Mon, 19 Mar 2007 15:19:08 -0700, Richard
wrote:

After I have entered a formula into a cell, the formula appears not the
result. When I check the formula it shows the correct result but does not
appear in the cell. I have tried it with different formulas, even very easy
ones, with the same results. This also does not happen in all cells. I
copied the formula to a cell above the one I wanted it in and it worked fine.
What is causing the formula to appear in the cell instead on the result?