ex6-09 Name of first column should be "scratches per item", not "searches"

ex9-90 should be ex9-92.  This exercise was 9-90 in the 5th edition.

ex12-35 is not the correct data.  Those data are from ex12-35 in the 5th
edition and that problem is not used in the 6th edition.

ex13-18 is the wrong data.  Not sure where it came from.

ex13-50 should be ex13-51

ex13-64 should be ex13-68

ex13-65 should be ex13-69

ex13-66 should be ex13-70

ex13-67 should be ex13-71

ex13-69 should be ex13-73

ex13-71 should be ex13-75

ex13-72 should be ex13-76

No data available for ex13-65

No data available for ex13-66

exp13-13 has the last column labelled "Absorbability (%)".  In the
text it is "Adsorbability (%)".