Hướng dẫn trả lời:
a) `-3/5 + (- 7/24) + 19/24`
`= -3/5 + [(- 7/24) + 19/24]`
`= -3/5 + 12/24`
`= -3/5 + 1/2`
`= -6/10 + 5/10`
`= -1/10`
b) `-5/9*2/13 + (-5/9)*11/13 + 1 5/9`
`= -5/9*(2/13 + 11/13) + 14/9`
`= -5/9*13/13 + 14/9`
`= -5/9*1 + 14/9`
`= -5/9 + 14/9`
`= 9/9`
`= 1`