This function calculates a date specified by year, month, day and displays it in the cell's formatting. The default format of a cell containing the DATE function is the date format, but you can format the cells with any other number format.
DATE(year; month; day)
In you can set from which year a two-digit number entry is recognized as 20xx.
If the values for month and day are higher, they are carried over to the next digit. If you enter =DATE(00;12;31) the result will be "12/31/00." If, on the other hand, you enter =DATE(00;13;31) the result will be "1/31/01."
DATE("00;1;1") yields 1/1/00