@Linh3782142

Giải thích các bước giải:

`1)`

`a)A=5/19+(-5)/3+(-21)/37+14/19+(-16)/37`

`A=(5/19+14/19)+[(-21)/37+(-16)/37]+(-5)/3`

`A=1+(-1)+(-5)/3`

`A=0+(-5)/3`

`A=(-5)/3`

Vậy `A=(-5)/3`

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`b)B=32/37+5/12+7/37+7/12+5/16+11/16`

`B=(32/37+7/37)+(5/12+7/12)+(5/16+11/16)`

`B=39/37+1+1`

`B=39/37+37/37+37/37`

`B=113/37`

Vậy `B=113/37`

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Bài `2)`

`a)A=11/17+(-8/19)+(-3/4)+6/17-30/19`

`A=(11/17+6/17)+[(-8/19)-30/19]+(-3/4)`

`A=1+(-38/19)+(-3/4)`

`A=1+(-2)+(-3/4)`

`A=4/4+(-8/4)+(-3/4)`

`A=(-7/4)`

Vậy `A=(-7/4)`

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`b)B=(-3)/31+(-6)/17+1/25+(-28)/21+(-11)/17+(-1)/5`

`B=[(-3)/31+(-28)/31]+[(-6)/17+(-11)/17]+[1/25+(-1)/5]`

`B=(-1)+(-1)+(-4)/25`

`B=(-54)/25`

Vậy `B=(-54)/25`

Đáp án + Giải thích các bước giải:

` 1) `

` a) A=5/19+{-5}/3+{-21}/37+14/19+{-16}/37 `

` =(5/19+14/19)+({-21}/37+{-16}/37)+{-5}/3 `

` =19/19+{-37}/37+{-5}/3 `

` =1+(-1)+{-5}/3 `

` =0+{-5}/3 `

` ={-5}/3 `

` b) B=32/37+5/12+7/37+7/12+5/16+11/16 `

` =(5/12+7/12)+(5/16+11/16)+(32/37+7/37) `

` =12/12+16/16+39/37 `

` =1+1+39/37 `

` =2+39/37 `

` =113/37 `

` 2) `

` a) A=11/17+(-8/19)+(-3/4)+6/17-30/19 `

` =11/17-8/19-3/4+6/17-30/19 `

` =(11/17+6/17)+(-8/19-30/19)+(-3/4) `

` =17/17+(-38/19)+(-3/4) `

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

` =-1+(-3/4) `

` =-7/4 `

` b) B={-3}/31+{-6}/17+1/25+{-28}/31+{-11}/17+{-1}/5 `

` =({-3}/31+{-28}/31)+({-6}/17+{-11}/17+(1/25+{-1}/5) `

` ={-31}/31+{-17}/17+{-4}/25 `

` =-1+(-1)+{-4}/25 `

` =-2+{-4}/25 `

` ={-54}/25 `

` #owen `