a)`(1 5/8 : 3 1/4 ) . 100 = 50%`
b) `(12,5 : 2,5) . 100 = 500%`
Bài 2:
`-217+88+117`
`= (-217 + 117 ) + 88 `
`= -100 + 88`
`= -12`
`1/15 + 3/2 - 2/3`
`= 2/30 + 45/30 - 20/30`
`= 9/10`
`2/3 - 5/ 7 . 14 / 25`
`= 2/3 . 5.14/7.25`
`= 2/3 - 2/5`
`= 2/3 + ( -2/50)`
`= 10/15 + -6/15 `
`= 4/15`
`25% - 1 1/2 + 0,5 . 12/5`
`= 1/4 - 3/2 + 1/2 . 12/5 `
`= -5/4 + 6/5 `
`= -1/20`