thực hiện phép tính ( 1 cách hợp lí nếu có thể )
a , 27 . 97 – 27 . 17 + 80 . 73
b , ( – 33 ) + 36 + ( – 39 ) + 42 + ( – 45 ) + 48
c , ( 3^15 . 27 – 2^15 . 2 ) : 3^18
d , – 2989 + [ 989 – ( 297 : 3^2 + 2^2 . 3^3 )]
thực hiện phép tính ( 1 cách hợp lí nếu có thể ) a , 27 . 97 – 27 . 17 + 80 . 73 b , ( – 33 ) + 36 + ( – 39 ) + 42 + ( – 45 ) + 48 c , ( 3^15 . 27 –
By Gianna
`27 . 97 – 27 . 17 + 80 . 73`
`=27.(97-27)+80.73`
`=27.80+80.73`
`=80.(27+73)`
`=80.100`
`=8000`
`( – 33 ) + 36 + ( – 39 ) + 42 + ( – 45 ) + 48`
`=(36-33)+(42-39)+(48-45)`
`=3+3+3`
`=9`
`( 3^15 . 27 – 2^15 . 2 ) : 3^18`
`=(2^18-2^16):3^18`
`=1-2^16:3^18`
`=1-(2^16)/(3^18)`
`- 2989 + [ 989 – ( 297 : 3^2 + 2^2 . 3^3 )]`
`=- 2989 + [989 – ( 33 + 108 )`
`=-2000-141`
`=-2141`
`a)27 . 97 – 27 . 17 + 80 . 73`
`=27.(97-17)+80.73`
`=27.80+80.73`
`=80.(27+73)`
`=80.100`
`=8000`
`b)( – 33 ) + 36 + ( – 39 ) + 42 + ( – 45 ) + 48`
`=[(-33)+36]+[(-39)+42]+[(-45)+48]`
`=3+3+3`
`=9`
`c)( 3^15 . 27 – 2^15 . 2 ) : 3^18`
`=(3^15 . 3^3 – 2^16):3^18`
`=(3^18-2^16):3^18`
`=3^18:3^18-2^16:3^18`
`=1-2^16:3^18`
(Kết quả tạm thời để vậy)
`d)- 2989 + [ 989 – ( 297 : 3^2 + 2^2 . 3^3 )]`
`=-2989+[989-(33+108)]`
`=-2989+[989-141]`
`=-2989+989-141`
`=-2000-141`
`=-2141`