`a ) 148,32 + 270,84 = 419,16`

 `148,32 `

`+`

 `270,84 `

___________

 `419,16 `

--------------------------------------

`b ) 197,25 - 92,73 = 104,52`

 `197,25`

`-`

 ` 92,73`

___________

 `104,52`

---------------------------------------

`c ) 34,6 xx 5,7 = 197,22`

 `34,6`

`xx`

 `  5,7`

____________

  `2422`

`1730`

_____________

`197,22`

------------------------------------------

`d ) 28,8 : 4,5 = 6,4`

`288` I_`45`_

`270` I `6,4`

______

  `18`

  `18`

_______

    `0`