Excel stores dates as serial numbers. So, your data in cell B3 is actually
39177. It is the Cell Formatting that has been applied to cell B3 that
causes it to display as 4/05/2007.

If cell B3 is referenced from another cell (like A3), it is the 39177 that
is carried over. Normally, the same Cell Formatting could be applied to cell
A3 as well, giving the same display results. But, since you've added the
text string "<=", a date format can no longer be applied to this cell.

Try this in cell A3:

="<="&TEXT(B3,"m/dd/yyyy")

HTH,
Elkar

"Daniel" wrote:

hi

when my B3 cell with date 4/05/2007, I don't know why the A3 cell display
serial number

My A3 cell with formula ="<="&B3

Can you explain this?

Thanks
Daniel