$Problem =~ /(\d+)    # one or more digits
             \s*      # zero or more whitespace
             ([-+\/*]) # operator (1 char only)
             \s*      # zero or more whitespace
             (\d+)/x; # one or more digits
my $Number1    = $1;
my $Number2    = $3;
my $Operator   = $2;

my $Answer;

my $Code = "$1 $2 $3"; # we're confident this is safe
$Answer = eval "$Code";