`( -1/5 ) + 3/12 ) + ( - 3 )/4`
`= ( - 12 )/60 + 15/60 + ( - 45 )/60`
`= 3 /60 + ( - 45 )/60`
`= ( - 42 )/60 = ( - 7 )/10`
___________________________________
`75% - 1 1/2 + 0,5 : 5/12`
`= 3/4 - 3/2 + 1/2 : 5/12`
`= 3/4 - 3/2 + 6/5`
`= 15/20 - 30/20 + 24/20`
`= ( - 15 )/20 + 24/20`
`= 9/20`
_______________________________
`( - 4 )/11 . 2/5 + 6/11 . ( - 3 )/10`
`= ( - 8 )/55 + ( - 9 )/55`
`= ( - 17 )/55`
