`(-1/4 + 7/33 - 5/3) - (-15/12 + 6/11 - 48/49)`
`= -1/4 + 7/33 - 5/3 + 5/4 - 6/11 + 48/49`
`= (-1/4 + 5/4) + (7/33 - 5/3 - 6/11) + 48/49`
`= ( \frac{-1+5}{4}) + ( 7/33 - 55/33 - 18/33) + 48/49`
`= 1 + (-2) + 48/49`
`= -1 + 48/49`
`= -49/49 + 48/49`
`= -1/49`