Any help would be appreciated...I'm rather stuck!
It's a mock exam and annoyingly they provided no solutions for me to work from...grrr....
I don't see the point of that using the inclusion-exclusion theorm...arg...this is the annoying thing about not having the solutions...don't know how they want us to do it...
Thankyou for your reply Plato
EDIT: WAIT NEVER MIND I GET IT NOW!! Silly me was thinking it was the actual numbers, rather than how many were in the set!