tính nhanh: a) 2.3/7 + (2/9 - 1.3/7) - 5/3 : 1/9 c) (377/-231 - 123/89 + 34/791) . (1/6 - 1/8 - 1/24)

2 câu trả lời

`a ) 2 . 3/7 + (2/9 - 1 . 3/7 ) - 5/3 : 1/9`

`= 6/7 + (2/9 - 3/7 ) - 15`

`= 6/7 + 2/9 - 3/7 - 15`

`= (6/7 - 3/7 ) + 2/9 - 15`

`= 3/7 + 2/9 - 15`

`= 41/63 - 15`

`= -904/63`

`b ) (377/(-231) - 123/89 + 34/791) . (1/6 - 1/8 - 1/24 )`

`= (377/(-231) - 123/89 + 34/791) . ( 4/24 - 3/24 - 1/24 )`

`= (377/(-231) - 123/89 + 34/791) . 0`

`= 0`

`#dtkc`