I began converting the original numbers to decimal (base 10), but decided that 5 points are not worth that much aggravation.
At that point, I wondered whether I could just write it down and do it like any old other subtraction exercise. I've never done that before with hex numbers, but I found that I could !
The only place you have to be extra careful is in the third place, where you have to subtract '9' from '2'. In order to do that, you have to borrow one from the 'F'. That makes the 'F' an 'E', and it makes the '2' an '18', from which you can then easily subtract the '9'. The difference of '2E9A' then jumps right out.
