diff --git a/gaboshlib/g_num_valid_number.sh b/gaboshlib/g_num_valid_number.sh
index e131520..c33bb70 100644
--- a/gaboshlib/g_num_valid_number.sh
+++ b/gaboshlib/g_num_valid_number.sh
@@ -1,14 +1,18 @@
 function g_num_valid_number {
-  [ -z "$1" ] && return 1
-  local f_arg=( "0" "$@" )
-  local i
-  for (( i=0; i<=$#; i++ ))
+  local arg
+  for arg in "$@"
   do
-    if ! [[ ${f_arg[$i]} =~ ^(-)?(\.)?[0-9]+(\.)?([0-9]+)?$ ]]
+    if ! [[ $arg =~ ^(-)?(\.)?[0-9]+(\.)?([0-9]+)?$ ]]
     then
-      echo "\"${f_arg[$i]}\": Not a valid number" 1>&2
+      echo "\"$arg\": Not a valid number" 1>&2
       g_traceback
       return 1
     fi
   done
+  if [ -z "$1" ]
+  then
+    echo "No argument given" 1>&2
+    g_traceback
+    return 2
+  fi
 }
diff --git a/gaboshlib/g_percentage-diff.bashfunc b/gaboshlib/g_percentage-diff.bashfunc
index 973ca35..d2440f2 100644
--- a/gaboshlib/g_percentage-diff.bashfunc
+++ b/gaboshlib/g_percentage-diff.bashfunc
@@ -5,11 +5,18 @@ function g_percentage-diff {
   local g_to=$2
   unset g_percentage_diff_result
   g_num_valid_number "$g_from" "$g_to" || return 1
-  g_calc "${g_from} == 0"
-  [ ${g_calc_result} -eq 1 ] && return 1
-  g_calc "${g_to} == 0"
-  [ ${g_calc_result} -eq 1 ] && return 1
-  g_calc "100/${g_from}*(${g_to}-${g_from})"
-  #g_percentage_diff_result=$(printf -- "%.2f" "${g_calc_result}")
-  printf -v g_percentage_diff_result -- "%.2f" "${g_calc_result}"
+  g_calc "$g_from == 0"
+  if [ $g_calc_result -eq 1 ] 
+  then
+    g_echo_note "$0: ERR: g_from=$g_from"
+    return 2
+  fi
+  g_calc "$g_to == 0"
+  if [ $g_calc_result -eq 1 ]
+  then
+    g_echo_note "$0: ERR: g_to=$g_to"
+    return 3
+  fi
+  g_calc "100 / $g_from * ( $g_to - ( $g_from ) )" || return 4
+  printf -v g_percentage_diff_result -- "%.2f" $g_calc_result
 }