How can I show posts or value data which not in a specific category

Hello,
I have a question and this is my problem:
I have a category 'A' which has 3 sub-categories : a,b,c.

Now,I have a value data :"hello world!".
I want to show it for displaying in 3 cats: a,b,c and don't show in category 'A'.
I used in_category() ,but the problem is that I have many sub-categories in category 'A' ( not only 3) .

So,I don't want type in_category() in many times .
I can't find any things which can solve my problem.
Hope you can help me!
Thanks a lot.