45
Event A. There are 8 main dishes served 8 at a time, and the order doesn't matter. This is 8 C 8 which is equal to 1.
Event B. There are 10 distinct side dishes taken 2 at a time and the order doesn't matter. 10 combination 2 = 45.
Considering the fundamental counting principle we know to multiply events A and B which is 1 x 45 = 45.