а) 2/3 + 1/6 = 4/6 + 1/6 = 5/6.
б) 12 - 9 3/7 = 11 7/7 - 9 3/7 = 2 4/7.
в) 1 1/3 * 1 1/2 = 4/3 * 3/2 = 12/6 = 2.
г) 36,12 : 12 = 3,01.