--- a/runtime/doc/change.txt
+++ b/runtime/doc/change.txt
@@ -1,4 +1,4 @@
-*change.txt*    For Vim version 7.0aa.  Last change: 2004 Nov 30
+*change.txt*    For Vim version 7.0aa.  Last change: 2004 Dec 17
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -351,7 +351,8 @@ The CTRL-A and CTRL-X commands work for 
 octal and hexadecimal numbers and alphabetic characters.  This depends on the
 'nrformats' option.
 - When 'nrformats' includes "octal", Vim considers numbers starting with a '0'
-  to be octal.  Other numbers are decimal and may have a preceding minus sign.
+  to be octal, unless the number includes a '8' or '9'.  Other numbers are
+  decimal and may have a preceding minus sign.
   If the cursor is on a number, the commands apply to that number; otherwise
   Vim uses the number to the right of the cursor.
 - When 'nrformats' includes "hex", Vim assumes numbers starting with '0x' or
@@ -365,9 +366,13 @@ octal and hexadecimal numbers and alphab
 For numbers with leading zeros (including all octal and hexadecimal numbers),
 Vim preserves the number of characters in the number when possible.  CTRL-A on
 "0077" results in "0100", CTRL-X on "0x100" results in "0x0ff".
+There is one exception: When a number that starts with a zero is found not to
+be octal (it contains a '8' or '9'), but 'nrformats' does include "octal",
+leading zeros are removed to avoid that the result may be recognized as an
+octal number.
 
 Note that when 'nrformats' includes "octal", decimal numbers with leading
-zeros are impossible because they are indistinguishable from octal numbers.
+zeros cause mistakes, because they can be confused with octal numbers.
 
 The CTRL-A command is very useful in a macro.  Example: Use the following
 steps to make a numbered list.