4 2/7 * 6 2/3 - 3,6 * 1/3 + 4 5/7 * 6 2/3 - 1/3 * 5,4 = (4 2/7 * 6 2/3 + 4 5/7 * 6 2/3) - (3,6 * 1/3 + 1/3 * 5,4) = 6 2/3 * (4 2/7 + 4 5/7 ) - 1/3 * (3,6 + 5,4) = 20/3 * 9 - 1/3 * 9 = 9 * (20/3 - 1/3) = 9 * 19/3 = 3*19 = 57 ( или = 20/3 * 9 - 1/3 * 9 = 60-3=57)
3.6 + 5.4 = 9
4 2/7 + 4 5/7 = 8 7/7 = 9