(2/7-2/3):1ц 1/7 + 0,9*(-5/9)-0,6:(-1,2) = -1/3
1) 2/7 - 2/3 = 6/21 - 14/21 = -8/21
2) -8/21 : 1ц 1/7 = -8/21 * 7/8 = -7/21 = -1/3
3) 0,9*(-5/9) = 9/10 * (-5/9) = -5/10 = -1/2
4) 0,6:(-1,2) = 6/10*(-10/12) = -6/12 = -1/2
5) -1/3 + (-1/2) = -1/3 - 1/2 = -2/6 - 3/6 = -5/6
6) -5/6 - (-1/2) = -5/6 +1/2 = -5/6 + 3/6 = -2/6 = -1/3