bài 1 tính a)25/38+7/38-10/38=. b)15/9×4/32 bài 2 thực hiện phép tính a)3/4+4/5-2/10 b)1/14+3/16+5/14+5/16

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1. `text{bài 1 tính}`

   `a)25/38+7/38-10/38`

   `= \frac{25 + 7 – 10}{38}`

   `= 22/28`

   `=11/19`

   `b) 15/9 . 4/32`

   `= 15/9 . 1/8`

   `= 15/72`

   `= 5/24`

   bài 2)

   `a)3/4+4/5-2/10`

   `= 15/20 + 16/20 – 4/20`

   =`\frac{15+16-4}{20}`

   `=27/20`

   `b)1/14+3/16+5/14+5/16`

   `= ( 1/14 + 5/14) + ( 3/16 + 5/16)`

   `= 3/7 + 1/2`

   `= 6/14 + 7/14`

   `= 13/14`

   `c)8/19xx12/13+8/19xx14/13`

   `= 8/19 xx ( 12/13 + 14/13)`

   `= 8/19 xx  2`

   `= 16/19`

   `d)14/11xx(6/4-2/5):5/2`

   `= 14/11 xx ( 30/20 – 8/20) : 5/2`

   `= 14/11 xx 11/10 : 5/2`

   `= 14/11 xx 11/25`

   `= 14/25`

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2. Đáp án:

    

   Giải thích các bước giải:

    `a) 25/38+ 7/38- 10/38`

   `= (25+ 7- 10)/38`

   `= 22/38`

   `= 11/19`

   `b) 15/9× 4/32`

   `= 5/3× 1/8`

   `= 5/24`

   `2)`

   `a) 3/4+ 4/5- 2/10`

   `= 3/4+ 4/5- 1/5`

   `= 15/20+ 16/20- 4/20`

   `= 27/20`

   `b) 1/14+ 3/16+ 5/14+ 5/16`

   `= (1/14+ 5/14)+ (3/16+ 5/16)`

   `= 3/7+ 1/2`

   `= 6/14+ 7/14`

   `= 13/14`

   `c) 8/19× 12/13+ 8/19× 14/13`

   `= 8/19× (12/13+ 14/13)`

   `= 8/19× 2`

   `= 16/19`

   `d) 14/11× (6/4- 2/5): 5/2`

   `= 14/11× (30/20- 8/20).  2/5`

   `= 14/11× 11/10. 2/5`

   `= 7/5· 2/5`

   `= 14/25`

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