Verified answer

! - факториал, например 4! = 1 * 2 * 3 * 4 = 24

6! 7! - 4! 5! = 1 * 2 * 3 * 4 * 5 * 6 * 1 * 2 * 3 * 4 * 5 * 6 * 7 - 1 * 2 * 3 * 4 * 1 * 2 * 3 * 4 * 5 = 3 628 800 -  2 880 =  3 625 920