178.
а) 2/3 + 0,6 = 2/3 + 6/10 = 2/3 + 3/5 = 10/15 + 9/15 = 19/15 = 1 4/15
б) 1 1/6 - 0,5 = 1 1/6 - 5/10 = 1 1/6 - 1/2 = 1 1/6 - 3/6 = 7/6 - 3/6 = 4/6 = 2/3
в) 0,3 * 5/9 = 3/10 * 5/9 = 1/2 * 1/3 = 1/6
г) 8/11 : 0,4 = 8/11 : 4/10 = 8/11 : 2/5 = 8/11 * 5/2 = 4/11 * 5/1 = 20/11 = 1 9/11