52/45-(3/3/5-1/7/9) * (1/2-1/3) все в подробностях

52/45 - (3_3/5 - 1_7/9) * (1/2 - 1/3 ) = 23/27

          4           1            3       2

1)  3_3/5 - 1_ 7/9 = 3_27/45 - 1_35/45 = 2_72/45 - 1_35/45 = 1_37/45

2) 1/2 - 1/3 = 3/6 - 2/6 = 1/6

3) 1_37/45 * 1/6 = 82/45 * 1/6 = (82*1)/(45*6) = 82/270

4) 52/45 - 82/270 = 312/270 - 82/270 = (312-82)/270 = 230/270 = 23/27