`a) -1/2 + 1/2 . -6/7`
`=-1/2 + -3/7`
`=-13/14`
`b)1/2 + 1/3 + -3/4`
`=6/12 + 4/12 + -9/12`
`=1/12`
`c)2/15 . 5/8 - 5/6 . -2/3`
`=1/12 - -5/9`
`=17/36`
`d)(2/3)^2=4/9`
`e)(-0,5)^2=0,25`
Bài 2:
`a) (-1/3)^3 . (-1/3)^2.(-1/3)`
`=(-1/3)^6`
`=1/729`
`b)2^7 : 2^4 = 2^3 = 8`
`c)[(1/2)^3]^2=(1/2)^6=1/64`