For essentially the same reason that ++75 is 76 and not 86: 

c:\@Work\Perl\monks>perl -wMstrict -le
"my $s = '75';
 printf qq{++'$s' -> };
 ++$s;
 print qq{'$s'};
"
++'75' -> '76'

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Why would a "carry" ("B" -> "C") be generated by incrementing from "e" to "f"?

Give a man a fish:  <%-{-{-{-<

In reply to Re^7: How the auto-increment operator works? by AnomalousMonk
in thread How the auto-increment operator works? by zapdos

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