The answer to exercise marked [BB]can be found in the Back of the Book.(a) [BB] Change the...

The answer to exercise marked [BB]can be found in the Back of the Book.

(a) [BB] Change the third and sixth digits of the ISBN 2-42-978329-0 so that the resulting number is not a valid ISBN.

(b) Change the third and sixth digits of the ISBN in (a) so that the resulting number is still valid.

(c) Show that any two digits of an ISBN can always be changed so that the errors would not be detected by the test in (6).

(a) [BB]

(b)

(c)

(d) [BB]

(e)

(f)