giúp mình bài này với ạ

`a) 1/6 + 5/4`

`= 2/12 + 15/12`

`= (2+15)/12`

`= 17/12`

`----------`

`b) 6/13 + 14/39`

`= 18/39 + 14/39`

`= (18+14)/39`

`= 32/39`

`----------`

`c) 12/11 - 7/19 + 12/19`

`= 12/11 - (7/19 + 12/19)`

`= 12/11 - 1`

`= 12/11 - 11/11`

`= (12-11)/11`

`= 1/11`

`---------`

`d) 5/7 * 2/11 + 5/7 * 9/11 - 5/7`

`= 5/7 * (2/11 + 9/11) - 5/7`

`= 5/7 * 1 - 5/7`

`= 5/7 - 5/7`

`= 0`

$\boxed{\color{green}{\text{#𝓖𝓻𝓮𝓮𝓷}}}$