Question

tính nhanh: 7/15-5/7+23/15+5/7-3/5

 

Answer 1

`7/15 - 5/7 + 23/15 + 5/7 - 3/5`

`= (7/15+ 23/15) + (-5/7 + 5/7) - 3/5`

`= 30/15 - 3/5`

`= 2 - 3/5`

`= 10/5 - 3/5`

`= 7/5`

Answer 2

`7/15 - 5/7 + 23/15 + 5/7 - 3/5`

`= (7/15 + 23/15)+ (5/7 - 5/7)  - 3/5`

`= 30/15 + 0/7 - 3/5`

`= 2 + 0 - 3/5`

`= 10/5 - 3/5`

`= 7/5`