(21/22 - 5/11) - (22/39 - 3/13)

1) 21/22 - 5/11 = 21/22 - 10/22. =. 11/22. 2) 22/39 - 3/13. =. 22/39. - 9/39 =. 13/39. 3) 11/22 - 13/39. =. ( 429 - 286)/ 858. = 143/858 = 11/66

получается = -2.509091