25.99-25.96+25 18.52+18.48-800 15.145-15.45+500 giúp mik với ạ

`25.99-25.96+25`

`=25.99-25.96+25.1`

`=25.(99-96+1)`

`=25.(3+1)`

`=25.4`

`=100`

____________________________

 `18.52+18.48-800`

`=18.(52+48)-800`

`=18.100-800`

`=1800-800`

`=1000`

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` 15 . 145 - 15.45 + 500`

`= 15 . ( 145 - 45 ) + 500`

`= 15. 100 + 5 . 100`

`= 100 .  ( 15 + 5)`

`= 100 . 20`

`=2000`