Mike,
I do not understand number 6 in the absolute value section of your book. Why can’t |0| + |7| = 7? Zero is even and 7 is odd.

I think you may be misinterpreting the question. Here’s #6:

The question is asking which choice could not equal the sum of a and b when |a| + |b| = 7. The value of a or b could be zero, as you point out, but that’s not what the question is asking.