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Đáp án:

Câu `1`:

`a)A = (10 2/9 + 2 3/5) - 6 2/9`

     ` = 10 2/9 + 2 3/5 - 6 2/9`

     ` = (10 2/9 - 6 2/9) + 2 3/5`

     ` = 4 + 13/5`

    ` = 20/5 + 13/5`

    ` = 33/5`

`b) B = 11 3/13 - ( 2 4/7 + 5 3/13)`

      ` = 11 3/13 - 2 4/7 - 5 3/13`

      ` = (11 3/13 - 5 3/13) - 2 4/7`

      ` = 6 - 18/7`

      ` = 42/7 - 18/7`

      ` = 24/7`

`c) C = (6 4/9 + 3 7/11) - 4 4/9`

      ` = 6 4/9 + 3 7/11 - 4 4/9`

      ` = (6 4/9 - 4 4/9) + 3 7/11`

      ` = 2 + 40/11`

      ` = 22/11 + 40/11`

      ` = 62/11`

`d) D = 13 8/9 . 4 5/6 - 7 8/9 . 4 5/6`

       ` = 4 5/6 . ( 13 8/9 - 7  8/9)`

        ` = 29/6 . 6`

        ` = 29`