а) 1/4 + 4/7 + 9/28 = 7/28 + 16/28 + 9/28 = 32/28 = 8/7 = 1 1/7
б) 1/5 + 3/10 + 7/20 = 4/20 + 6/20 + 7/20 = 17/20
в) 3/20 + 7/30 + 2/40 = 18/120 + 28/120 + 6/120 = 52/120 = 13/30
г) 17/20 + 23/30 + 11/60 = 51/60 + 46/60 + 11/60 = 108/60 = 9/5 = 1 4/5
д) 3/20 + 7/30 + 9/59 = 531/3540 + 826/3540 + 540/3540 = 1897/3540 - здесь, видимо, ошибка в записи?
е) 7/40 + 11/70 + 13/30 = 147/840 + 132/840 + 364/840 = 426/840 = 643/840
а) 1/4 + 4/7 + 9/28 = 7/28 + 16/28 + 9/28 = 32/28 = 8/7 = 1 1/7
б) 1/5 + 3/10 + 7/20 = 4/20 + 6/20 + 7/20 = 17/20
в) 3/20 + 7/30 + 2/40 = 18/120 + 28/120 + 6/120 = 52/120 = 13/30
г) 17/20 + 23/30 + 11/60 = 51/60 + 46/60 + 11/60 = 108/60 = 9/5 = 1 4/5
д) 3/20 + 7/30 + 9/59 = 531/3540 + 826/3540 + 540/3540 = 1897/3540 - здесь, видимо, ошибка в записи?
е) 7/40 + 11/70 + 13/30 = 147/840 + 132/840 + 364/840 = 426/840 = 643/840