use Date::Calc qw(Add_Delta_Days);

my $date_str = "24/08/2005";

my @start = reverse split "/", $date_str;   # convert to (YYYY, MM, DD) array

my @d = Add_Delta_Days(@start,3);
printf "%02d/%02d/%4d\n", $d[2,1,0];   # print DD/MM/YYYY format

@d = Add_Delta_Days(@start,10);
printf "%02d/%02d/%4d\n", $d[2,1,0];   # print DD/MM/YYYY format