Tính: a) 17$\frac{2}{31}$ - ( $\frac{15}{17}$ + 6$\frac{2}{31}$ ) b) 27$\frac{51}{59}$ - ( 25$\frac{51}{59}$ - 1$\frac{1}{3}$ ) c) $\frac{-4}{5}$ . $\frac{11}{13}$ + $\frac{4}{5}$ . $\frac{-2}{13}$ - $\frac{1}{5}$

2 câu trả lời

Đáp án:

 

Giải thích các bước giải:

a `17 2/31 – ( 15/17 + 6 2/31 ) `

`=17 2/31 – 15/17 – 6 2/31`

`= 11 – 15/17`

`=172/17`

b`27 51/59 – ( 25 51/59 – 1 1/3)`

`= 27 51 /59 – 25 51/59 + 1 1/3`

`= 2 +1 1/3`

`=10/3`

c`-4/5 . 11/13 + 4/5 . -2/13 – 1/5`

`=4/5 . [(-11/13) + (-2/13) ] – 1/5`

`=4/5 . (-1) – 1/5`

`=-4/5 – 1/5`

`=-5/5 `

`=-1`

Đáp án:

 a)

`17 2/31 - (15/17 + 6 2/31)`

`=17 2/31 - 15/17 - 6 2/31`

`=(17 2/31 - 6 2/31) - 15/17`

`=11 - 15/17`

`=172/17` hay `10 2/17`

b)

`27 51/59 - (25 51/59 - 1 1/3)`

`=27 51/59 - 25 51/59 + 1 1/3`

`=(27 51/59 - 25 51/59) + 1 1/3`

`=2 +1 1/3`

`=10/3` hay `3 1/3`

c)

`(-4)/5 . 11/13 + 4/5 . (-2)/13 - 1/5`

`=(-44)/65 + (-8)/65 -1/5 `

`= (-4)/5 - 1/5`

`=-1`

`#Hien`

Giải thích các bước giải: