∴m=66.

(2)∵ The average annual growth rate is (4.78-3.88) ∵ 5 = 0.225 (Ben),

∴2065 438+04 reading volume: 4.78+0.225≈5 (this);

(3)990÷0.66×5=7500,

Therefore, in 20 14 years, the total reading of adult citizens in this community was about 7500 books.

So the answer is: 5; 7500.