a) a = 2 * 2 * 3 * 5 * 5, b = 2 * 3 * 3 * 3 * 5.
НОК(a, b) = 2 * 2 * 3 * 3 * 3 * 5 * 5 = 900
б) a = 3 * 3 * 7 * 7, b = 2 * 3 * 3 * 5 * 7 * 7.
НОК(a, b) = 2 * 3 * 3 * 5 * 7 * 7 = 4410
в) a = 2 * 2 * 5 * 5 * 11, b = 2 * 2 * 3 * 5 * 11.
НОК(a, b) = 2 * 2 * 3 * 5 * 5 * 11 = 3300
г) a = 2 * 5 * 5 * 7, b = 2 * 2 * 5 * 5 * 7.
НОК(a, b) = 2 * 2 * 5 * 5 * 7 = 700