$\text{Đáp án+Giải thích các bước giải:}$
`a)``3`` 2/5``+ ``5 ``3/10`
`=``17/5``+``53/10`
`=``34/10``+``53/10`
`=``87/10`
`b)`` 4`` 3/5`` -``3`` 2/7`
`=``23/5``-``23/7`
`=``161/35``-``115/35`
`=``46/35`
`c)``4`` 4/15``xx`` 2`` 1/12`
`=``64/15``xx``25/12`
`=``80/9`
`d)``4`` 9/10``:``3`` 9/15`
`=``49/10``:``18/5`
`=``49/10``:``5/18`
`=``49/36`