After reading the comments, I realized now that the mechanism behind the problem is more complicated than I thought. First, the decimal separator is a comma and not a full stop. Second, Excel classifies the input value as a 'date' value but represents it using the 'number' format.
One solution to the posted problem is to change the decimal separator, and it can be done from Excel,
Options -> Advanced -> Editing options -> Decimal separator. If this is fixed, Excel would not have classified the input value as a 'date' value.
The decimal separator is not something I would immediately consider because, who would use a comma as the decimal separator? And yet, interestingly and surprisingly, half the world actually uses it (https://en.wikipedia.org/wiki/Decimal_separator).
However, I did recognize the
43125 as a 'date' value in numerical form. If we take away the issue about the decimal separator, a similar example would be
1-25, which Excel would interpret as a 'date' value and under the 'number' format gives
45658.00. More confusingly is that Excel allows custom formats so that the 'date' value can appear as
1,25 or any other form.
I used a lot of 'date' values in spreadsheets for calculations and they can be annoying. Occasionally when I reopen these spreadsheets, Excel (or Openoffice) would think they know better and automatically convert these date columns from the 'date' format to the 'number' format for no reasons. In these situations,
right-click mouse -> Format Cells -> Number and reset to the correct format for the cells/columns would recover the data.