câu 1)
`a) 1/2 . ( 2/9 + 3/7 - 5/27)`
`= 1/2 . ( 41/63 - 5/27)`
`= 1/2 . 88/189`
`= 44/189`
`b)5/6 . 11/4 - 5/4 . 23/6`
`= 55/24 - 115/24`
`= -5/2`
`g) 125% . ( -1/2)² : ( 1 5/16- 1,5) + 2021^0`
`= 5/4 . 1/4 : ( 21/16 - 3/2) + 1`
`= 5/4 . 1/4 : -3/16 + 1`
`= 5/16 : -3/16 + 1`
`=-5/3 + 1`
`= -5/3 + 3/3`
`= -2/3`
bài 2)
`a) -3/7 + 15/26 - ( 2/13 - 3/7)`
= `-3/7 + 15/26 - 2/13 + 3/7`
`= ( -3/7 + 3/7) + ( 15/26 - 2/13)`
`= 0 + ( 15/26 - 4/26)`
`= 0 +11/26`
`= 11/26`
`e)9/16 . 13/4 - 9/4 . 5/16 + 9/16 . 17/4`
`= 9/16 . ( 13/4 + 17/4) - 9/4 . 5/16`
`= 9/16 . 15/2 - 9/4 . 5/16`
`= 135/32 - 9/4 . 5/16`
`=15/8 . 9/4 - 9/4 . 5/16`
`= 9/4 . ( 15/8 - 5/16)`
`= 9/4 . 25/16`
`= 225/64`
