`A = -5/2 : 3/4 + 2/3`
`= -5/2 . 4/3 + 2/3`
`= -10/3 + 2/3`
`= -8/3`
`B= 1/2 - ( 2/3 + 1/10)`
`= 1/2 - 2/3 - 1/10`
`= ( 1/2 - 1/10) - 2/3`
`= 2/5 - 2/3`
`=6/15` - `10/15`
`= 6/15 + -10/15`
`= -4/15`
`C = ( 11/12 : 33/16) . 3/5`
`= ( 11/12 . 16/33) . 3/5`
`= 4/9 . 3/5`
`= 4/15`