Scalar found where operator expected at temp.pl line 7, near "$add $first_number"
	(Missing operator before $first_number?)
Global symbol "$first_number" requires explicit package name at temp.pl line 6.
Global symbol "$second_number" requires explicit package name at temp.pl line 6.
Global symbol "$third_number" requires explicit package name at temp.pl line 6.
Global symbol "$fourth_number" requires explicit package name at temp.pl line 6.
Global symbol "$fifth_number" requires explicit package name at temp.pl line 6.
Global symbol "$sixth_number" requires explicit package name at temp.pl line 6.
Global symbol "$add" requires explicit package name at temp.pl line 7.
syntax error at temp.pl line 7, near "$add $first_number "
Global symbol "$first_number" requires explicit package name at temp.pl line 7.
Global symbol "$second_number" requires explicit package name at temp.pl line 7.
Global symbol "$third_number" requires explicit package name at temp.pl line 7.
Global symbol "$fourth_number" requires explicit package name at temp.pl line 7.
Global symbol "$fifth_number" requires explicit package name at temp.pl line 7.
Global symbol "$sixth_number" requires explicit package name at temp.pl line 7.
Execution of temp.pl aborted due to compilation errors.