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Bài 3

`1)`

`2 3/5 - 1 2/3`

= `13/5 - 5/3`

= `39/15 - 25/15`

= `14/15`

`2)`

`3 3/7 + 2 1/2`

= `24/7 + 5/2`

= `83/14`

`3)`

`-3 1/2 - 2 1/4`

= `-7/2 - 9/4`

= `-14/2 - 9/4`

= `-23/4`

`4)`

`-2 1/2 - 3 1/4`

= `-5/2 - 13/4`

= `-10/4 - 13/4`

= `-23/4`

`5)`

`-4 1/2 + 2 3/10`

= `-9/2 + 23/10`

= `-45/10 + 23/10`

= `-11/5`

`6)`

`-6 1/7 - (-7 1/6)`

= `-43/7 + 43/6`

= `43/42`