diff --git a/gaboshlib/g_num_valid_number.sh b/gaboshlib/g_num_valid_number.sh
index d8f6d83..4568a3b 100644
--- a/gaboshlib/g_num_valid_number.sh
+++ b/gaboshlib/g_num_valid_number.sh
@@ -1,4 +1,5 @@
 function g_num_valid_number {
+  [ -z "$@" ] && return 1
   local f_arg=( "0" "$@" )
   for (( i=0; i<=$#; i++ ))
   do