Решите (3целых1/7)-(-1целая9/14)=
3 1/7 + 1 9/14 = 3 2/14 + 1 9/14 = 4 11/14
(3.1/7) - (1.9/14) = 3/7 - (-9/14) = 3/7 + 9/14 = 15/14 = 1.1/14