I pressed cltr-shift-enter (I tried enter but it gave me dd-mm-yy
as the final answer)

Dates in Excel are really numbers, formatted differently. Using just "Enter" by itself actually gives the right answer, but to change the format select the cell and use
right-click Format cells number
to see the format choices.

By changing the format of the value 41353, for example, you can get it to look any of these ways and many mo
41353
03/20/13
41,353.000
4135300.00%
Wednesday, March 20, 2013
3/20/13 12:00 AM
4.14E+04
€41,353.00

Ragardless of the format, the value behaves the same way in arithmetic calculations.