# Common Mistakes on HW 10

- #10 of section 5.5: Be sure to use the right counting principle.
#18 of section 5.4: Ae careful to not count the wrong sequence. The answer should be C(29,49), not C(30,50)

6(c) of section 5.4: If you are using Cantor-Bernstein, you should say so.

#33 of section 5.3: Be sure to not leave out the first or last terms when applying the binomial theorem, and also the binomial theorem (1 + x)^n = 1 + nx + \dots holds for all x values. (despite claims to the contrary, it's fine also for negative x)

'a – b!' and '(a – b)!' are not the same