Вычислите используя характеристики сложения и умножения 1)1 30/37+2,5+3 7/37 2)(1 7/25+8/9)-7/25

1) 1 30/37 + 2,5 + 3 7/37 = 7 1/2 либо 7,5.
    1 30/37 = (1 * 37 + 30)/37 = 67/37.
    2,5 = 2 5/10 = (2 * 10 + 5)/10 = 25/10 сократим на 5 = 5/2.
    3 7/37 = (3 * 37 + 7)/37 = 118/37.
    5 = 4 2/2 = (4 * 2 + 2)/2 = 10/2.
 1. 67/37 + 118/37 = 185/37 = 5.
 2. 10/2 + 5/2 = 15/2 = 7 1/2.
2) (1 7/25 + 8/9) - 7/25 = 28/45.
    1 7/25 = (1 * 25 + 7)/25 = 32/25.
 1. 32/25 + 8/9 = (228 + 200)/225 = 428/225.
 2. 428/225 - 7/25 = (428 - 63)/225 = 365/225 сократим на 5 = 73/45 = 1 28/45.
3) 15/29 + (14/299 - 2/3) = - 2669/26013.
 1. 14/299 - 2/3 = (42 - 598)/897 = - 556/897.
 2. 15/29 - 556/897 = (13455 - 16124)/26013 = - 2669/26013.
4) (8 4/15 + 11/20) - 4/15 = 8 11/20.
    8 4/15 = (8 * 15 + 4)/15 = 124/15.
 1. 124/15 + 11/20 = (496 + 33)/60 = 529/60.
 2. 529/60 - 4/15 = (529 - 16)/60 = 513/60 на 3 = 171/20 = 8 11/20.

1. 2 4/5 + 1,2 = (14 + 6)/5 = 20/5 = 4 обратное: 1/4.
2. 2 4/5 - 1,2 = (14 - 6)/5 = 8/5 обратное: 5/8.
3. 2 4/5 * 1,2 = (14 * 6)/(5 * 5) = 84/25 обратное: 25/84.
4. 2 4/5 / 1,2 = (14 * 5)/(6 * 5) = 70/30 = 7/3 оборотное: 3/7.
    2 4/5 = (2 * 5 + 4)/5 = 14/5.
    1,2 = 1 2/10 = (1 * 10 + 2)/10 = 12/10 на 2 = 6/5.