A variable is like a pigeon hole for data.
It's where the data lives when it's not busy being data.
Most programming languages have different types of variables for different types of data. But, Perl is a little different in this respect.
In Perl, all data types are based on one simple type called a scalar. Scalar data can be either text or numeric and sometimes both. This simplification makes its possible for you to write your programs without worrying about what data type a particular variable is.
More complex data is built by aggregating scalars into other structures like arrays and hashes.
These aggregations are convenient at times, and allow you to write more complex programs without writing more complex programs.