Алла7 лет назад
1) 3 3/7 - 3,25 + 2 1/14 = (3 * 7 + 3)/7 - 325/100 + (2 * 14 + 1)/14 = 24/7 - 13/4 + 29/14 = 4 * 24/(4 * 7) - 7 * 13/(4 * 7) + 2 * 29/(2 * 14) = (96 - 91 + 58)/28 = 63/28 = 9/4;
2) (3 3/7 - 2 1/14) + 3,25 = 96/28 - 58/28 + 91/28 = (96 - 58 + 91)/28 = 129/28;
3) (3 6/14 - 2 1/14) + 3,25 = 48/14 - 29/14 + 325/100 = (48 - 29)/14 + 13/4 = 2 * 19/(2 * 14) + 7 * 13/(4 * 7) = (38 + 91)/28 = 129/28;
4) 1 5/14 + 3,25 = (1 * 14 + 5)/14 + 325/100 = 19/14 + 13/4 = 38/28 + 91/28 = 129/28.