Tính nhanh: a)27.(35-49)-35.(27-49) b)75.(25-17)-25.(75-17) 09/11/2021 Bởi Abigail Tính nhanh: a)27.(35-49)-35.(27-49) b)75.(25-17)-25.(75-17)
$a)$ $27.(35-49)-35.(27-49) = 27.35 – 27.49 – 35.27 – 35.49$ $= 27.35 – 35.27 – 27.49 – 35.49$ $= 27.(35 -35) – 49.(27 – 35)$ $= 27.0 – 49.(27-35)$ $= 0 – 49.(-8)$ $= 0 – (-392)$ $= 0 + 392$ $= 392$ $b)$ $75.(25-17) – 25.(75 – 17) = 75.25 – 75.17 – 25.75 – 25.17$ $= 75.25 – 25.75 – 75.17 – 25.17$ $= 75.(25 -25) -17.(75-25)$ $= 75.0 – 17.50$ $= 0 – 850$ $= -850$ Bình luận
Đáp án: Giải thích các bước giải: `a)27.(35-49)-35.(27-49)` `=27.35-27.49-35.27-35.49` `=27(35-35)-49(27-35)` `=0-49.(-8)=0-(-392)0+392=392` `b)75(25-17)-25(75-17)` `=75.25-75.17-25.75-25.17` `=75(25-25)-17(75-25)` `=0-17.50` `=0-850=-850` Bình luận
$a)$ $27.(35-49)-35.(27-49) = 27.35 – 27.49 – 35.27 – 35.49$
$= 27.35 – 35.27 – 27.49 – 35.49$
$= 27.(35 -35) – 49.(27 – 35)$
$= 27.0 – 49.(27-35)$
$= 0 – 49.(-8)$
$= 0 – (-392)$
$= 0 + 392$
$= 392$
$b)$ $75.(25-17) – 25.(75 – 17) = 75.25 – 75.17 – 25.75 – 25.17$
$= 75.25 – 25.75 – 75.17 – 25.17$
$= 75.(25 -25) -17.(75-25)$
$= 75.0 – 17.50$
$= 0 – 850$
$= -850$
Đáp án:
Giải thích các bước giải:
`a)27.(35-49)-35.(27-49)`
`=27.35-27.49-35.27-35.49`
`=27(35-35)-49(27-35)`
`=0-49.(-8)=0-(-392)0+392=392`
`b)75(25-17)-25(75-17)`
`=75.25-75.17-25.75-25.17`
`=75(25-25)-17(75-25)`
`=0-17.50`
`=0-850=-850`