13/21 * (9/26-2 целых 3//3)3сверзу решите

13/21*(9/26-2 3/13) - (-2/3)³= - 23/54

1) 9/26- 2 3/13= 9/26-29/13= 9/26-58/26= - 49/26= - 1 1/6
2) 13/21*(-1 1/6)= 13/21*(-7/6)= -13/18
3) -2/3³= -2/3*(-2/3)*(-2/3)= -8/27
4) -13/18-(-8/27)= -39/54+16/54= -23/54