- 9/30/2008 from George Zhang:
p.41

Question: For what values of A is the five digit number 967A0 divisible by 2, 3, 4, and 6?p.42 solution should be fixed to:

To check whether 967A0 is divisible by 2, 3, 4, and 6, we just need to check whether it is a multiple of 2^{2}=4 and 3. It is a multiple of 4 if 2·A + 0 is a multiple of 4. This is true whenever A is an even number. 967A0 is a multiple of 3 if 9+6+7+A+0=22+A is a multiple of 3. This happens for A=2, 5, and 8. Hence, 967A0 is a multiple of 3 and 4 if and only if A=2 or 8.