In cell A1, type “19/6/2002”, assuming that your Excel’s default date format is DD/MM/YY. If not, just key in the date in a way which Excel will recongise.
Go to cell B1 type “=A1+1000”
Press [ENTER]. If a huge number appears, congrats, you are almost done. if a “!VALUE” appear insteads, check you have key in the date properly.
Right click on cell B1, select Format Cells, click on the Number tab, and chooses date.