444 Найдите произведение: a) 4 3/7 * 7; б) 9 2/5 * 5; в) 3 * 3 6/9; г) 7 5/14 * 7; д) 5 7/21.

a) 4 3/7 * 7 = (4 + 3/7) * 7 = 4 * 7 + 3/7 * 7 = 28 + 3 = 31 б) 9 2/5 * 5 = (9 + 2/5) * 5 = 9 * 5 + 2/5 * 5 = 45 + 2 = 47 в) 3 * 3 6/9 = 3 * (3 + 6/9) = 3 * (3 + 2/3) = 3 * (9/3 + 2/3) = 3 * 11/3 = 11 г) 7 5/14 * 7 = (7 + 5/14) * 7 = 7 * 7 + 5/14 * 7 = 49 + 5/2 = 49 + 2 1/2 = 51 1/2 д) 5 7/21 = 5 1/3 = 16/3