1) Найдите сумму и сократите итог: а) 2целых 7/15 + 3целых

1) Найдём сумму:
а) 2 7/15 + 3 13/15 = 37/15 + 58/15 = 95/15 сократим на 5 = 19/3 = 6 1/3.
    2 7/15 = (30 + 7)/15 = 37/15.
    3 13/15 = (3 * 15 + 13)/15 = 58/15.
б) 4 8/13 + 2 6/13 = 60/13 + 32/13 = 92/13 = 7 1/13.
    4 8/13 = (4 * 13 + 8)/13 = 60/13.
    2 6/13 = (2 * 13 + 6)/13 = 32/13.
в) 5 5/12 + 1 11/12 = 65/12 + 23/12 = 88/12 сократим на 4 = 22/3 = 7 1/3.
    5 5/12 = (5 * 12 + 5)/12 = 65/12.
    1 11/12 = (1 * 12 + 11)/12 = 23/12.
2) Найдём разность:
а) 7 - 5/6 = 42/6 - 5/6 = 37/6 = 6 1/6.
    7 = 6 6/6 = (6 * 6 + 6)/6 = 42/6.
б) 14 - 8 6/7 = 98/7 - 62/7 = 36/7 = 5 1/7.
    14 = 13 7/7 = (13 * 7 + 7)/7 = 98/7.
    8 6/7 = (8 * 7 + 6)/7 = 62/7.
в) 6 2/9 - 4 7/9 = 56/9 - 43/9 = 13/9 = 1 4/9.
    6 2/9 = (6 * 9 + 2)/9 = 56/9.
    4 7/9 = (4 * 9 + 7)/9 = 43/9.
3)Сравним:
6 7/19 - 2 18/19 lt; 1 14/25 + 2 13/25.
1. 6 7/19 - 2 18/19 = 121/19 - 56/19 = 65/19 = 3,4.
    6 7/19 = (6 * 19 + 7)/19 = 121/19.
    2 18/19 = (2 * 19 + 18)/19 = 56/19.
2. 1 14/25 + 2 13/25 = 39/25 + 63/25 = 102/25 = 4,08.
    1 14/25 = (1 * 25 + 14)/25 = 39/25.
    2 13/25 = (2 * 25 + 13)/25 = 63/25.
4) Вычислим:
14 - а - в, если а = 6 5/7, в = 3/14.
14 - 6 5/7 - 3/14 = 196/14 - 47/7 - 3/14 = (196 - 94 - 3)/14 = 99/14 = 7 1/14.
6 5/7 = (6 * 7 + 5)/7 = 47/7.
14 = 13 14/14 = (13 * 14 + 14)/14 = 196/14.