Let use Google for a funny non-conformist inquiry: Will George Bush be
re-elected

?
searching <bush president> yields 7 290 000 pages
searching <bush -president> yields 7 350 000 pages
Let us now do a basic check: searching <bush> should yield 14 640 000
pages (the sum of the two: pages with the word bush AND the word
president, plus pages with the word bush WITHOUT the word president).
Alas! it yields 32 000 000 pages. More than twice as much !
Using page counts in Google could be very useful... if they were
right.
My question is: How does Google calculate its page counts?