11. (10 points) From $1001,1002,1003,1004,1005,1006,1007,1008,1009$, select any four numbers so that their sum is even. How many different ways are there to do this?
【Analysis】First, analyze that if the result is even, it can be divided into $0, 2, 4$ odd numbers. Add up each result.
【Solution】According to the problem, we know:
Based on the result of the four numbers being even. There must be 0 odd numbers, 2 odd numbers, or 4 odd numbers. In $1001,1002,1003,1004,1005,1006,1007,1008,1009$, the number of odd numbers is 5, and the number of even numbers is 4.

When there are 0 odd numbers, there is 1 case.
When there are 2 odd numbers and 2 even numbers, there are $C_{5}^{2} C_{4}^{2}=60$ cases.
When choosing 4 odd numbers, there are 5 cases.
$60+5+1=66$ (cases)
Answer: There are 66 ways to choose.