I have inherited a spreadsheet that contains columns of numbers to represent
a day (dd), columns with numbers for month (mm) and another with the year
(yyyy)

How can I combine the 3 cells in a row to produce a date cell (dd/mm/yyyy)?

e.g.
A7 = 7
A8 = 5
A9 = 2001
but I need 07/05/2001