1 files changed, 5 insertions, 0 deletions
diff --git a/lib/Bot/Games/Game/24.pm b/lib/Bot/Games/Game/24.pm
index df317c6..ef87734 100644
--- a/lib/Bot/Games/Game/24.pm
+++ b/lib/Bot/Games/Game/24.pm
@@ -25,6 +25,11 @@ sub _init {
 sub turn {
     my $self = shift;
     my ($player, $expr) = @_;
+
+    my $numbers = join ',', sort split(/[-\+\*\/\(\)]+/, $expr);
+    my $solution = join ',', sort split(' ', $self->state);
+    return "invalid numbers" unless $numbers eq $solution;
+
     my $eval = $self->_evaluate($expr);
     if ($eval == 24) {
         $self->is_over("$player wins!");