Precision in language is crucial to writing your code. In this case, you're saying a present value is that value, post-incremented. Strictly speaking, that's true, but writing the code in this fashion is apt to trip the unwary -- author included:

#!/usr/bin/perl =w
use strict;

#1137973

my $number=8;

for(my $i=0; $i<3; $i++) {
     print "present value of \$i is $i and the number is: $number \n";
     print "   now printing \$number++: " . $number++ . "\n"; # NOTE O
+UTPUT!
     print "!! NOW, NOT EARLIER the post-increment occurs AFTER Ln 10\
+n";
     print "     and after post-increment, \$i is STILL $i but number 
+is: $number\n\-----------\n";
}

=head

present value of $i is 0 and the number is: 8
   now printing $number++: 8   # ie, unchanged!
!! NOW, NOT EARLIER the post-increment occurs AFTER Ln 10
     and after post-increment, $i is STILL 0 but number is: 9
-----------
present value of $i is 1 and the number is: 9
   now printing $number++: 9
!! NOW, NOT EARLIER the post-increment occurs AFTER Ln 10
     and after post-increment, $i is STILL 1 but number is: 10
-----------
present value of $i is 2 and the number is: 10
   now printing $number++: 10
!! NOW, NOT EARLIER the post-increment occurs AFTER Ln 10
     and after post-increment, $i is STILL 2 but number is: 11
-----------

=cut
[download]

You're cheese-paring the size of your script by a few bytes at the expense of clarity; better to post-increment in a standalone line of code -- for clarity.

UPDATE: ... or, as Athanasius pointed out in a message, a (standalone) pre-increment (++$number)could also be used effectively ... but that would REALLY require precise language... as in something like "the next number is: " or maybe "oops, off by one."