`2/3 + 3/8 -5/12`
`= 16/24 + 9/24 -5/12`
`= 25/24 -5/12`
`= 25/24 - 10/24`
`=15/24`
`= 5/8`
`------`
`-3/14 + 3/8 -1/4`
`= 9/56 -1/4`
`= 9/56 - 14/56`
`=-5/56`
`------`
`5/9 . ( 3/5 + 3/10)`
`=5/9 . (6/10 + 3/10)`
`= 5/9 . 9/10`
`= 45/90`
`=1/2`
# môn toán nha bạn
