359.
а. 1/7 < 4/21 (3/21 и 4/21)
б. 3/5 > 8/15 ( 9/15 и 8/15)
в. 3/5 > 11/20 (12/20 и 11/20)
г. 4/7 = 16/28 (4/7 и 4/7)
360
а. 1/2 + 1/3 = 3/6+2/6 = 5/6
б. 1/4 +2/5 = 5/20 + 8/20 = 13/20
в. 2/3+1/4 = 8/12 + 3/12 = 11/12
г. 3/4 + 2/5 = 15/20 + 8/20 = 23/20 = 1 3/20
е. 3/4 - 1/3 = 9/12 - 4/12 = 5/12