Date addition error

[hc]

Hi,

I am using excel 2007
say if i type in "1-Jan" in cell A1, "15" in cell A2, and "=A1+A2" in cell A3
cell A3 should show "16-Jan"
In my case, whether i set A1 and/or A3 to date format or not, A3 returns
"#VALUE!"

other than using the DATE(year,month,day) function, how should I fix this
problem? i.e. "1-Jan" + "15" = "16-Jan"

thank you in advance

 

[Gary''s Student]

when typing, use:
1/1