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Đáp án + Giải thích các bước giải:

`1) 3/2 + 5/7 + 1/2 + 16/7`

`= ( 3/2 + 1/2 ) + ( 5/7 + 16/7 )`

`= 2 + 3`

`= 5`

`2)  1/2 + 1/3 + 5/7`

`= 21/42 + 14/42 + 30/42`

`= 65/42`

`3) 1/4 + 1/5 + 1/2`

`= 5/20 + 4/20 + 10/20`

`= 19/20`

`4) 1/2 xx 3/7 + 1/2 xx 4/7 `

`= 1/2 xx ( 3/7 + 4/7 )`

`= 1/2 xx 1`

`= 1/2`

`5) 11/12 : 7/24 xx 21/22`

`= 11/12 xx 24/7 xx 21/22`

`= 22/7 xx 21/22`

`= 3`

`6) 1/3 + 4/5 + 2/3 + 1/2 + 1/5`

`= ( 1/3 + 2/3 ) + ( 4/5 + 1/5 ) + 1/2`

`= 1 + 1 + 1/2`

`= 5/2`

`7) 5/12 : 7/4 - 25/18 : 35/6`

`= 5/12 xx 4/7 - 25/18 xx 6/35`

`= 5/42 - 5/21`

`=-5/42`

`8) 15/2 xx 3/4 - 3/4 xx 7/2`

`= 3/4 xx ( 15/2 - 7/2 )`

`= 3/4 xx 8`

`=6`

`QH`